Fix issue with multiple properties and emit store.

Fix issue with multiple properties and emit store.

We used to have a parse error for conflicting property keys. This check
was removed to match ES6 (SpiderMonkey & Chakra already made this change).
Since this check was removed we ended up with a few new cases when
generating code. For example, accessors always generated code even if
those should have been shadowed by a data property.

BUG=v8:3856
LOG=Y
R=adamk, dslomov@chromium.org

Committed: https://crrev.com/cd661fdc277a75dec8506f038e3d5904b29de141
Cr-Commit-Position: refs/heads/master@{#26441}

[arv (Not doing code reviews), 2015-02-02 18:04:47]

Cleanup test a bit

[arv (Not doing code reviews), 2015-02-02 18:05:18]

arv@chromium.org changed reviewers:
+ dslomov@chromium.org

[arv (Not doing code reviews), 2015-02-02 18:05:18]

PTAL

[adamk, 2015-02-02 19:07:25]

lgtm, but another pair of eyes from dslomov wouldn't hurt.

[arv (Not doing code reviews), 2015-02-02 19:25:35]

Dmitry, care to take a look?

[arv (Not doing code reviews), 2015-02-03 16:58:32]

Ping!

[Dmitry Lomov (no reviews), 2015-02-04 10:42:48]

lgtm

[arv (Not doing code reviews), 2015-02-04 20:20:22]

New patchsets have been uploaded after l-g-t-m from dslomov@chromium.org

[arv (Not doing code reviews), 2015-02-04 20:20:26]

git rebase

[arv (Not doing code reviews), 2015-02-04 20:20:38]

The CQ bit was checked by arv@chromium.org

[commit-bot: I haz the power, 2015-02-04 20:20:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/895693002/40001

[commit-bot: I haz the power, 2015-02-04 20:44:10]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-02-04 20:44:28]

Patchset 3 (id:??) landed as
https://crrev.com/cd661fdc277a75dec8506f038e3d5904b29de141
Cr-Commit-Position: refs/heads/master@{#26441}