X87: Reland "[es6] Better support for built-ins subclassing."

X87: Reland "[es6] Better support for built-ins subclassing."

  port 4490ce85205d3504dc0bf444f5e8b3deb04cbb06 (r31701).

  original commit message:
    Original issue's description:
    > [es6] Better support for built-ins subclassing.
    >
    > Create proper initial map for original constructor (new.target) instead of doing prototype
    > transition on the base constructor's initial map. This approach fixes in-object slack tracking
    > for subclass instances.
    > This CL also fixes subclassing from String.
    >
    > BUG=v8:3101, v8:3330
> LOG=Y
    >
    > Committed: https://crrev.com/cd5f48302a502154a0106d12e3066bd563c6340c
    > Cr-Commit-Position: refs/heads/master@{#31680}

    It also fixes typed array map smashing done during typed array initialization.

BUG=

Committed: https://crrev.com/62acae2436733fcfcce684bfb9280f84cb508cbd
Cr-Commit-Position: refs/heads/master@{#31704}

[zhengxing.li, 2015-11-02 09:34:09]

zhengxing.li@intel.com changed reviewers:
+ chunyang.dai@intel.com, weiliang.lin@intel.com

[Weiliang, 2015-11-02 09:39:41]

The CQ bit was checked by weiliang.lin@intel.com

[Weiliang, 2015-11-02 09:39:42]

lgtm

[commit-bot: I haz the power, 2015-11-02 09:39:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1432483003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1432483003/1

[commit-bot: I haz the power, 2015-11-02 09:59:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-02 10:00:21]

Patchset 1 (id:??) landed as
https://crrev.com/62acae2436733fcfcce684bfb9280f84cb508cbd
Cr-Commit-Position: refs/heads/master@{#31704}