[turbofan] Add test case for stores to properties that are also present on prototype.

[turbofan] Add test case for stores to properties that are also present on prototype.

R=verwaest@chromium.org
BUG=v8:4470
LOG=n

Committed: https://crrev.com/2ab54f109e04bbf2fd0e34959535d70bc253dfac
Cr-Commit-Position: refs/heads/master@{#31517}

[Benedikt Meurer, 2015-10-23 10:53:09]

Hey Toon,

The regression test we talked about offline.
Please take a look.

Thanks,
Benedikt

[Toon Verwaest, 2015-10-23 10:55:38]

lgtm

[Benedikt Meurer, 2015-10-23 10:55:58]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-10-23 10:56:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1407233006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1407233006/1

[commit-bot: I haz the power, 2015-10-23 12:09:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-23 12:09:59]

Patchset 1 (id:??) landed as
https://crrev.com/2ab54f109e04bbf2fd0e34959535d70bc253dfac
Cr-Commit-Position: refs/heads/master@{#31517}