Revert of [turbofan] Speculatively optimize string character access.

Revert of [turbofan] Speculatively optimize string character access. (patchset #1 id:1 of https://codereview.chromium.org/2905623003/ )

Reason for revert:
Changes layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/15867

See:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> [turbofan] Speculatively optimize string character access.
> 
> Add a protector cell for string bounds checks that is being used to
> protect speculative bounds for String.prototype.charCodeAt and
> String.prototype.charAt in TurboFan (and Crankshaft). This way we don't
> have the diamond in optimized code, which stands in the way of other
> optimizations for charCodeAt that are currently being worked on by
> petermarshall@.
> 
> BUG=v8:6391
> TBR=mlippautz@chromium.org
> R=petermarshall@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2905623003
> Cr-Commit-Position: refs/heads/master@{#45514}
> Committed: https://chromium.googlesource.com/v8/v8/+/9d8bd0551657d60c66b2f96544eecedfba1cba8a

TBR=petermarshall@chromium.org,mlippautz@chromium.org,bmeurer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6391
Review-Url: https://codereview.chromium.org/2900333002
Cr-Commit-Position: refs/heads/master@{#45521}
Committed: https://chromium.googlesource.com/v8/v8/+/a07218a56d51698b25dedbab1038f0b6865acfd2

[Michael Achenbach, 2017-05-24 17:04:25]

The CQ bit was checked by machenbach@chromium.org

[Michael Achenbach, 2017-05-24 17:04:25]

Created Revert of [turbofan] Speculatively optimize string character access.

[commit-bot: I haz the power, 2017-05-24 17:04:35]

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, 2017-05-24 17:04:45]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1495645465240460, "parent_rev":
"cdd9ed0879a6a33ab88278bdd6aafbf5e850d04f", "commit_rev":
"a07218a56d51698b25dedbab1038f0b6865acfd2"}

[commit-bot: I haz the power, 2017-05-24 17:04:56]

Description was changed from

==========
Revert of [turbofan] Speculatively optimize string character access. (patchset
#1 id:1 of https://codereview.chromium.org/2905623003/ )

Reason for revert:
Changes layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/bui...

See:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> [turbofan] Speculatively optimize string character access.
> 
> Add a protector cell for string bounds checks that is being used to
> protect speculative bounds for String.prototype.charCodeAt and
> String.prototype.charAt in TurboFan (and Crankshaft). This way we don't
> have the diamond in optimized code, which stands in the way of other
> optimizations for charCodeAt that are currently being worked on by
> petermarshall@.
> 
> BUG=v8:6391
> TBR=mlippautz@chromium.org
> R=petermarshall@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2905623003
> Cr-Commit-Position: refs/heads/master@{#45514}
> Committed:
https://chromium.googlesource.com/v8/v8/+/9d8bd0551657d60c66b2f96544eecedfba1...

TBR=petermarshall@chromium.org,mlippautz@chromium.org,bmeurer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6391
==========

to

==========
Revert of [turbofan] Speculatively optimize string character access. (patchset
#1 id:1 of https://codereview.chromium.org/2905623003/ )

Reason for revert:
Changes layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/bui...

See:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> [turbofan] Speculatively optimize string character access.
> 
> Add a protector cell for string bounds checks that is being used to
> protect speculative bounds for String.prototype.charCodeAt and
> String.prototype.charAt in TurboFan (and Crankshaft). This way we don't
> have the diamond in optimized code, which stands in the way of other
> optimizations for charCodeAt that are currently being worked on by
> petermarshall@.
> 
> BUG=v8:6391
> TBR=mlippautz@chromium.org
> R=petermarshall@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2905623003
> Cr-Commit-Position: refs/heads/master@{#45514}
> Committed:
https://chromium.googlesource.com/v8/v8/+/9d8bd0551657d60c66b2f96544eecedfba1...

TBR=petermarshall@chromium.org,mlippautz@chromium.org,bmeurer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6391

Review-Url: https://codereview.chromium.org/2900333002
Cr-Commit-Position: refs/heads/master@{#45521}
Committed:
https://chromium.googlesource.com/v8/v8/+/a07218a56d51698b25dedbab1038f0b6865...
==========

[commit-bot: I haz the power, 2017-05-24 17:04:57]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/a07218a56d51698b25dedbab1038f0b6865...