VM: Fix canonicalization of old-space allocated instances

VM: Fix canonicalization of old-space allocated instances

Instances of objects allocated in old-space would not get canonicalized properly,
resulting in duplicates of these instances on the heap.

This can be e.g. argument descriptors allocated in the background compiler thread.

This also fixes the same issue occurring with isolate reload.

Also, add a NoSafepointScope for consistency.

BUG=#27364
R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/cd05ee0c813437c7ed2cce160820f0bb47e97264

[Florian Schneider, 2016-09-20 00:15:28]

Description was changed from

==========
VM: Fix canonicalization of old-space allocated instances

Instances of objects allocated in old-space would not get canonicalized
properly,
resulting in duplicates of these instances on the heap.

This can be e.g. argument descriptors allocated in the background compiler
thread.

BUG=#27364
==========

to

==========
VM: Fix canonicalization of old-space allocated instances

Instances of objects allocated in old-space would not get canonicalized
properly,
resulting in duplicates of these instances on the heap.

This can be e.g. argument descriptors allocated in the background compiler
thread.

This also fixes the same issue occurring with isolate reload.

Also, add a NoSafepointScope for consistency.

BUG=#27364
==========

[Florian Schneider, 2016-09-20 00:15:36]

fschneider@google.com changed reviewers:
+ asiva@google.com

[siva, 2016-09-20 00:23:40]

lgtm

[Florian Schneider, 2016-09-20 00:27:12]

Description was changed from

==========
VM: Fix canonicalization of old-space allocated instances

Instances of objects allocated in old-space would not get canonicalized
properly,
resulting in duplicates of these instances on the heap.

This can be e.g. argument descriptors allocated in the background compiler
thread.

This also fixes the same issue occurring with isolate reload.

Also, add a NoSafepointScope for consistency.

BUG=#27364
==========

to

==========
VM: Fix canonicalization of old-space allocated instances

Instances of objects allocated in old-space would not get canonicalized
properly,
resulting in duplicates of these instances on the heap.

This can be e.g. argument descriptors allocated in the background compiler
thread.

This also fixes the same issue occurring with isolate reload.

Also, add a NoSafepointScope for consistency.

BUG=#27364
R=asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/cd05ee0c813437c7ed2cce160820f0bb47e97264
==========

[Florian Schneider, 2016-09-20 00:27:13]

Committed patchset #2 (id:20001) manually as
cd05ee0c813437c7ed2cce160820f0bb47e97264 (presubmit successful).