Fix spec-compliance bug in Array.prototype.join.

Fix spec-compliance bug in Array.prototype.join.

The code used to [[Get]] the first element twice instead of once, which can be
observed (one of the kangax tests does so).

R=rossberg
BUG=

Committed: https://crrev.com/c4f39389ea2dad857a2415a783bc7fbc4bdf0f6b
Cr-Commit-Position: refs/heads/master@{#34383}

[rossberg, 2016-02-29 16:45:50]

lgtm

[neis, 2016-03-01 08:13:25]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2016-03-01 08:13:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1747933002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1747933002/1

[commit-bot: I haz the power, 2016-03-01 08:17:27]

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

[commit-bot: I haz the power, 2016-03-01 08:17:28]

Try jobs failed on following builders:
  v8_linux_mips64el_compile_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_mips64el_compile_r...)

[neis, 2016-03-01 08:44:01]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2016-03-01 08:44:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1747933002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1747933002/1

[commit-bot: I haz the power, 2016-03-01 09:06:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-01 09:07:44]

Description was changed from

==========
Fix spec-compliance bug in Array.prototype.join.

The code used to [[Get]] the first element twice instead of once, which can be
observed (one of the kangax tests does so).

R=rossberg
BUG=
==========

to

==========
Fix spec-compliance bug in Array.prototype.join.

The code used to [[Get]] the first element twice instead of once, which can be
observed (one of the kangax tests does so).

R=rossberg
BUG=

Committed: https://crrev.com/c4f39389ea2dad857a2415a783bc7fbc4bdf0f6b
Cr-Commit-Position: refs/heads/master@{#34383}
==========

[commit-bot: I haz the power, 2016-03-01 09:07:45]

Patchset 1 (id:??) landed as
https://crrev.com/c4f39389ea2dad857a2415a783bc7fbc4bdf0f6b
Cr-Commit-Position: refs/heads/master@{#34383}