Fix behavior of return on yield*.

Fix behavior of return on yield*.

When calling the return method on a generator suspended inside a yield*, yield*
in turn calls return on its iterable.  If this results in a "done" iterator,
yield* must return immediately, thus terminating the generator.  For some
reason, we didn't terminate the generator but continued right after the yield*.

R=adamk@chromium.org
BUG=v8:5131
Committed: https://crrev.com/6dffb078048a8ff8c000ada468b86689cdcc82f8
Cr-Commit-Position: refs/heads/master@{#37310}

[neis, 2016-06-27 10:36:41]

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

[commit-bot: I haz the power, 2016-06-27 10:36:46]

Dry run: 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, 2016-06-27 11:00:18]

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

[commit-bot: I haz the power, 2016-06-27 11:00:19]

Dry run: This issue passed the CQ dry run.

[adamk, 2016-06-27 18:07:52]

lgtm

[neis, 2016-06-28 07:06:30]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2016-06-28 07:06:38]

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, 2016-06-28 07:09:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-28 07:11:05]

Description was changed from

==========
Fix behavior of return on yield*.

When calling the return method on a generator suspended inside a yield*, yield*
in turn calls return on its iterable.  If this results in a "done" iterator,
yield* must return immediately, thus terminating the generator.  For some
reason, we didn't terminate the generator but continued right after the yield*.

R=adamk@chromium.org
BUG=v8:5131
==========

to

==========
Fix behavior of return on yield*.

When calling the return method on a generator suspended inside a yield*, yield*
in turn calls return on its iterable.  If this results in a "done" iterator,
yield* must return immediately, thus terminating the generator.  For some
reason, we didn't terminate the generator but continued right after the yield*.

R=adamk@chromium.org
BUG=v8:5131

Committed: https://crrev.com/6dffb078048a8ff8c000ada468b86689cdcc82f8
Cr-Commit-Position: refs/heads/master@{#37310}
==========

[commit-bot: I haz the power, 2016-06-28 07:11:06]

Patchset 1 (id:??) landed as
https://crrev.com/6dffb078048a8ff8c000ada468b86689cdcc82f8
Cr-Commit-Position: refs/heads/master@{#37310}