Make climit and jslimit stack limits atomic.

Make climit and jslimit stack limits atomic.

This fixes TSAN failure caused by race between:
 - optimizing compiler thread setting climit
 - and json parser reading climit in the main thread.

BUG=

Committed: https://crrev.com/3a814e4c1afc3aee2badad7523b8e8ef6ae80e28
Cr-Commit-Position: refs/heads/master@{#27840}

[ulan, 2015-03-26 13:15:24]

ulan@chromium.org changed reviewers:
+ jochen@chromium.org

[ulan, 2015-03-26 13:15:24]

PTAL

[jochen (gone - plz use gerrit), 2015-03-26 13:17:09]

Heap::SetStackLimits vs JITted code is still a race, right?

[ulan, 2015-03-26 13:54:33]

On 2015/03/26 13:17:09, jochen wrote:
> Heap::SetStackLimits vs JITted code is still a race, right?
Yes, that race should be harmless since we acquire the lock on stack check
failure.

Upload new PS.

[jochen (gone - plz use gerrit), 2015-03-26 14:03:47]

lgtm

[ulan, 2015-04-15 10:44:31]

The CQ bit was checked by ulan@chromium.org

[ulan, 2015-04-15 10:44:32]

The patchset sent to the CQ was uploaded after l-g-t-m from jochen@chromium.org
Link to the patchset: https://codereview.chromium.org/1031223004/#ps40001
(title: "Rebase")

[commit-bot: I haz the power, 2015-04-15 10:44:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1031223004/40001

[commit-bot: I haz the power, 2015-04-15 11:37:12]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-04-15 11:37:25]

Patchset 3 (id:??) landed as
https://crrev.com/3a814e4c1afc3aee2badad7523b8e8ef6ae80e28
Cr-Commit-Position: refs/heads/master@{#27840}