Fix bug in yield* desugaring.

Fix bug in yield* desugaring.

In one corner case, we incorrectly returned a value without first wrapping it in
an iterator result object.

R=littledan@chromium.org
BUG=v8:5057
Committed: https://crrev.com/8154d977e4650bec931b27d52f62ba056d0d74c8
Cr-Commit-Position: refs/heads/master@{#36676}

[Dan Ehrenberg, 2016-06-02 09:14:36]

lgtm

[neis, 2016-06-02 09:16:38]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2016-06-02 09:16:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2034653002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2034653002/1

[commit-bot: I haz the power, 2016-06-02 09:42:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-02 09:44:06]

Description was changed from

==========
Fix bug in yield* desugaring.

In one corner case, we incorrectly returned a value without first wrapping it in
an iterator result object.

R=littledan@chromium.org
BUG=v8:5057
==========

to

==========
Fix bug in yield* desugaring.

In one corner case, we incorrectly returned a value without first wrapping it in
an iterator result object.

R=littledan@chromium.org
BUG=v8:5057

Committed: https://crrev.com/8154d977e4650bec931b27d52f62ba056d0d74c8
Cr-Commit-Position: refs/heads/master@{#36676}
==========

[commit-bot: I haz the power, 2016-06-02 09:44:07]

Patchset 1 (id:??) landed as
https://crrev.com/8154d977e4650bec931b27d52f62ba056d0d74c8
Cr-Commit-Position: refs/heads/master@{#36676}