Reland of Fix async/await memory leak

Reland of Fix async/await memory leak (patchset #1 id:1 of https://codereview.chromium.org/2348403003/ )

This patch closes a memory leak in async/await where the desugaring
was creating a situation analagous to that described in v8:5002.
Intermediate Promises were being kept alive, so a long-running loop
would cause linear memory usage on the heap. This patch returns
undefined to the 'then' callback passed into PerformPromiseThen
in order to avoid this hazard. Test expectations are fixed to remove
expecting extraneous events which occurred on Promises that are
now not given unnecessarily complex resolution paths before being
thrown away.

This patch is a reland; originally, tests which exercised the memory
exhaustion were checked in. Although it's possible to find good parameters
for running such tests locally, it is difficult to automate the tests
between the rock of timeouts and the hard place of too-small heaps
causing memory exhaustion in some modes even when there is no leak.

BUG=v8:5390
Committed: https://crrev.com/bf43f883c1e6bca974993375085fc63137846f0d
Cr-Commit-Position: refs/heads/master@{#39520}

[Dan Ehrenberg, 2016-09-19 23:23:21]

Created Reland of Fix async/await memory leak

[Dan Ehrenberg, 2016-09-19 23:26:58]

Description was changed from

==========
Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2348403003/ )

Reason for revert:
Removing two difficult to automate tests from otherwise good bug fix

Original issue's description:
> Revert of Fix async/await memory leak (patchset #5 id:160001 of
https://codereview.chromium.org/2348403002/ )
> 
> Reason for revert:
> Still causes issues on bot (sometimes!)
> 
> Original issue's description:
> > Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2354473002/ )
> >
> > Reason for revert:
> > Relanding with faster-running test
> >
> > Original issue's description:
> > > Revert of Fix async/await memory leak (patchset #5 id:80001 of
https://codereview.chromium.org/2334323006/ )
> > >
> > > Reason for revert:
> > > newly introduced test async-await-loop times out:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20...
> > >
> > > Original issue's description:
> > > > Fix async/await memory leak
> > > >
> > > > This patch closes a memory leak in async/await where the desugaring
> > > > was creating a situation analagous to that described in v8:5002.
> > > > Intermediate Promises were being kept alive, so a long-running loop
> > > > would cause linear memory usage on the heap. This patch returns
> > > > undefined to the 'then' callback passed into PerformPromiseThen
> > > > in order to avoid this hazard. Test expectations are fixed to remove
> > > > expecting extraneous events which occurred on Promises that are
> > > > now not given unnecessarily complex resolution paths before being
> > > > thrown away.
> > > >
> > > > BUG=v8:5390
> > > >
> > > > Committed: https://crrev.com/a0ba18e9634c5e2d439033ab61a77cff54f9af35
> > > > Cr-Commit-Position: refs/heads/master@{#39479}
> > >
> > > TBR=adamk@chromium.org,caitp@igalia.com,littledan@chromium.org
> > > NOTRY=true
> > > BUG=v8:5390
> > >
> > > Committed: https://crrev.com/196db1999da130019bbf8e3bd65977f840e8afaf
> > > Cr-Commit-Position: refs/heads/master@{#39493}
> >
> > TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > BUG=v8:5390
> >
> > Committed: https://crrev.com/e51482f01f26e0013e6377e85c4d2c41900e403c
> > Cr-Commit-Position: refs/heads/master@{#39508}
> 
> TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5390
> 
> Committed: https://crrev.com/3f366186e986f715d61a179fa223e2209b6fe882
> Cr-Commit-Position: refs/heads/master@{#39512}

TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org,machenbach@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5390
==========

to

==========
Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2348403003/ )

Reason for revert:
Removing two difficult to automate tests from otherwise good bug fix

Original issue's description:
> Revert of Fix async/await memory leak (patchset #5 id:160001 of
https://codereview.chromium.org/2348403002/ )
> 
> Reason for revert:
> Still causes issues on bot (sometimes!)
> 
> Original issue's description:
> > Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2354473002/ )
> >
> > Reason for revert:
> > Relanding with faster-running test
> >
> > Original issue's description:
> > > Revert of Fix async/await memory leak (patchset #5 id:80001 of
https://codereview.chromium.org/2334323006/ )
> > >
> > > Reason for revert:
> > > newly introduced test async-await-loop times out:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20...
> > >
> > > Original issue's description:
> > > > Fix async/await memory leak
> > > >
> > > > This patch closes a memory leak in async/await where the desugaring
> > > > was creating a situation analagous to that described in v8:5002.
> > > > Intermediate Promises were being kept alive, so a long-running loop
> > > > would cause linear memory usage on the heap. This patch returns
> > > > undefined to the 'then' callback passed into PerformPromiseThen
> > > > in order to avoid this hazard. Test expectations are fixed to remove
> > > > expecting extraneous events which occurred on Promises that are
> > > > now not given unnecessarily complex resolution paths before being
> > > > thrown away.
> > > >
> > > > BUG=v8:5390
> > > >
> > > > Committed: https://crrev.com/a0ba18e9634c5e2d439033ab61a77cff54f9af35
> > > > Cr-Commit-Position: refs/heads/master@{#39479}
> > >
> > > TBR=adamk@chromium.org,caitp@igalia.com,littledan@chromium.org
> > > NOTRY=true
> > > BUG=v8:5390
> > >
> > > Committed: https://crrev.com/196db1999da130019bbf8e3bd65977f840e8afaf
> > > Cr-Commit-Position: refs/heads/master@{#39493}
> >
> > TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > BUG=v8:5390
> >
> > Committed: https://crrev.com/e51482f01f26e0013e6377e85c4d2c41900e403c
> > Cr-Commit-Position: refs/heads/master@{#39508}
> 
> TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5390
> 
> Committed: https://crrev.com/3f366186e986f715d61a179fa223e2209b6fe882
> Cr-Commit-Position: refs/heads/master@{#39512}

TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org,machenbach@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOTREECHECKS=true
BUG=v8:5390
==========

[Dan Ehrenberg, 2016-09-19 23:27:03]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-19 23:27:08]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[adamk, 2016-09-19 23:29:06]

lgtm, but please rewrite the CL description (it's gotten very hard for my brain
to parse).

[Dan Ehrenberg, 2016-09-19 23:35:48]

Description was changed from

==========
Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2348403003/ )

Reason for revert:
Removing two difficult to automate tests from otherwise good bug fix

Original issue's description:
> Revert of Fix async/await memory leak (patchset #5 id:160001 of
https://codereview.chromium.org/2348403002/ )
> 
> Reason for revert:
> Still causes issues on bot (sometimes!)
> 
> Original issue's description:
> > Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2354473002/ )
> >
> > Reason for revert:
> > Relanding with faster-running test
> >
> > Original issue's description:
> > > Revert of Fix async/await memory leak (patchset #5 id:80001 of
https://codereview.chromium.org/2334323006/ )
> > >
> > > Reason for revert:
> > > newly introduced test async-await-loop times out:
https://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20...
> > >
> > > Original issue's description:
> > > > Fix async/await memory leak
> > > >
> > > > This patch closes a memory leak in async/await where the desugaring
> > > > was creating a situation analagous to that described in v8:5002.
> > > > Intermediate Promises were being kept alive, so a long-running loop
> > > > would cause linear memory usage on the heap. This patch returns
> > > > undefined to the 'then' callback passed into PerformPromiseThen
> > > > in order to avoid this hazard. Test expectations are fixed to remove
> > > > expecting extraneous events which occurred on Promises that are
> > > > now not given unnecessarily complex resolution paths before being
> > > > thrown away.
> > > >
> > > > BUG=v8:5390
> > > >
> > > > Committed: https://crrev.com/a0ba18e9634c5e2d439033ab61a77cff54f9af35
> > > > Cr-Commit-Position: refs/heads/master@{#39479}
> > >
> > > TBR=adamk@chromium.org,caitp@igalia.com,littledan@chromium.org
> > > NOTRY=true
> > > BUG=v8:5390
> > >
> > > Committed: https://crrev.com/196db1999da130019bbf8e3bd65977f840e8afaf
> > > Cr-Commit-Position: refs/heads/master@{#39493}
> >
> > TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > BUG=v8:5390
> >
> > Committed: https://crrev.com/e51482f01f26e0013e6377e85c4d2c41900e403c
> > Cr-Commit-Position: refs/heads/master@{#39508}
> 
> TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5390
> 
> Committed: https://crrev.com/3f366186e986f715d61a179fa223e2209b6fe882
> Cr-Commit-Position: refs/heads/master@{#39512}

TBR=adamk@chromium.org,caitp@igalia.com,hablich@chromium.org,machenbach@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOTREECHECKS=true
BUG=v8:5390
==========

to

==========
Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2348403003/ )

This patch closes a memory leak in async/await where the desugaring
was creating a situation analagous to that described in v8:5002.
Intermediate Promises were being kept alive, so a long-running loop
would cause linear memory usage on the heap. This patch returns
undefined to the 'then' callback passed into PerformPromiseThen
in order to avoid this hazard. Test expectations are fixed to remove
expecting extraneous events which occurred on Promises that are
now not given unnecessarily complex resolution paths before being
thrown away.

This patch is a reland; originally, tests which exercised the memory
exhaustion were checked in. Although it's possible to find good parameters
for running such tests locally, it is difficult to automate the tests
between the rock of timeouts and the hard place of too-small heaps
causing memory exhaustion in some modes even when there is no leak.

BUG=v8:5390
==========

[Dan Ehrenberg, 2016-09-19 23:36:05]

The CQ bit was unchecked by littledan@chromium.org

[Dan Ehrenberg, 2016-09-19 23:36:07]

The CQ bit was checked by littledan@chromium.org

[commit-bot: I haz the power, 2016-09-19 23:36:17]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-19 23:51:36]

Committed patchset #2 (id:140001)

[commit-bot: I haz the power, 2016-09-19 23:52:02]

Description was changed from

==========
Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2348403003/ )

This patch closes a memory leak in async/await where the desugaring
was creating a situation analagous to that described in v8:5002.
Intermediate Promises were being kept alive, so a long-running loop
would cause linear memory usage on the heap. This patch returns
undefined to the 'then' callback passed into PerformPromiseThen
in order to avoid this hazard. Test expectations are fixed to remove
expecting extraneous events which occurred on Promises that are
now not given unnecessarily complex resolution paths before being
thrown away.

This patch is a reland; originally, tests which exercised the memory
exhaustion were checked in. Although it's possible to find good parameters
for running such tests locally, it is difficult to automate the tests
between the rock of timeouts and the hard place of too-small heaps
causing memory exhaustion in some modes even when there is no leak.

BUG=v8:5390
==========

to

==========
Reland of Fix async/await memory leak (patchset #1 id:1 of
https://codereview.chromium.org/2348403003/ )

This patch closes a memory leak in async/await where the desugaring
was creating a situation analagous to that described in v8:5002.
Intermediate Promises were being kept alive, so a long-running loop
would cause linear memory usage on the heap. This patch returns
undefined to the 'then' callback passed into PerformPromiseThen
in order to avoid this hazard. Test expectations are fixed to remove
expecting extraneous events which occurred on Promises that are
now not given unnecessarily complex resolution paths before being
thrown away.

This patch is a reland; originally, tests which exercised the memory
exhaustion were checked in. Although it's possible to find good parameters
for running such tests locally, it is difficult to automate the tests
between the rock of timeouts and the hard place of too-small heaps
causing memory exhaustion in some modes even when there is no leak.

BUG=v8:5390

Committed: https://crrev.com/bf43f883c1e6bca974993375085fc63137846f0d
Cr-Commit-Position: refs/heads/master@{#39520}
==========

[commit-bot: I haz the power, 2016-09-19 23:52:03]

Patchset 2 (id:??) landed as
https://crrev.com/bf43f883c1e6bca974993375085fc63137846f0d
Cr-Commit-Position: refs/heads/master@{#39520}