Further ES2015 RegExp spec compliance fixes

Further ES2015 RegExp spec compliance fixes

- RegExp.prototype.toString() doesn't have any special handling of
  RegExp instances and simply calls the source and flags getters
- Use the original values of global and sticky, rather than based
  on the current flag getters, as specified in
  https://github.com/tc39/ecma262/pull/494

R=yangguo@chromium.org,adamk
LOG=Y
BUG=v8:4602
Committed: https://crrev.com/277f5bd0a3b548534d15a8be2afcd4b34cdd756f
Cr-Commit-Position: refs/heads/master@{#35225}

[Dan Ehrenberg, 2016-04-01 18:38:04]

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

[commit-bot: I haz the power, 2016-04-01 18:38:15]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1846303002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1846303002/1

[commit-bot: I haz the power, 2016-04-01 18:49:26]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-04-01 18:49:26]

Dry run: Try jobs failed on following builders:
  v8_linux64_avx2_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel/builds/...)

[Dan Ehrenberg, 2016-04-01 18:54:31]

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

[commit-bot: I haz the power, 2016-04-01 18:54:35]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1846303002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1846303002/20001

[commit-bot: I haz the power, 2016-04-01 19:16:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-04-01 19:16:58]

Dry run: This issue passed the CQ dry run.

[Yang, 2016-04-04 06:40:05]

lgtm

[Dan Ehrenberg, 2016-04-04 06:43:01]

The CQ bit was checked by littledan@chromium.org

[commit-bot: I haz the power, 2016-04-04 06:43:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1846303002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1846303002/20001

[commit-bot: I haz the power, 2016-04-04 07:05:55]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-04-04 07:06:28]

Description was changed from

==========
Further ES2015 RegExp spec compliance fixes

- RegExp.prototype.toString() doesn't have any special handling of
  RegExp instances and simply calls the source and flags getters
- Use the original values of global and sticky, rather than based
  on the current flag getters, as specified in
  https://github.com/tc39/ecma262/pull/494

R=yangguo@chromium.org,adamk
LOG=Y
BUG=v8:4602
==========

to

==========
Further ES2015 RegExp spec compliance fixes

- RegExp.prototype.toString() doesn't have any special handling of
  RegExp instances and simply calls the source and flags getters
- Use the original values of global and sticky, rather than based
  on the current flag getters, as specified in
  https://github.com/tc39/ecma262/pull/494

R=yangguo@chromium.org,adamk
LOG=Y
BUG=v8:4602

Committed: https://crrev.com/277f5bd0a3b548534d15a8be2afcd4b34cdd756f
Cr-Commit-Position: refs/heads/master@{#35225}
==========

[commit-bot: I haz the power, 2016-04-04 07:06:29]

Patchset 2 (id:??) landed as
https://crrev.com/277f5bd0a3b548534d15a8be2afcd4b34cdd756f
Cr-Commit-Position: refs/heads/master@{#35225}