X87: [es6] Introduce a dedicated JSIteratorResult type.

X87: [es6] Introduce a dedicated JSIteratorResult type.

port 72bc4b5c8a5c4279bcb8b340edbc8aa1c46d75a1 (r30557)

original commit message:

    Use a single JSIteratorResult type for all implementation provided
    iterator results (i.e. the String, Array and collection iterators,
    and also for generators).  This removes one source of unnecessary
    polymorphism in for-of loops.  It is accomplished by a new intrinsic
    %_CreateIterResultObject() that should be used to create iterator
    result objects from JavaScript builtins (there's a matching factory
    method for C++ code).

    Also restructure the %StringIteratorPrototype%.next() and
    %ArrayIteratorPrototype%.next() functions to be a bit more friendly
    to optimizing compilers.

BUG=

Committed: https://crrev.com/691f796f7297ec3076dc23a7d79bb7da7f1d10e1
Cr-Commit-Position: refs/heads/master@{#30610}

[chunyang.dai, 2015-09-06 10:21:33]

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

[chunyang.dai, 2015-09-06 10:21:33]

PTAL

[Weiliang, 2015-09-07 07:18:17]

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

[Weiliang, 2015-09-07 07:18:18]

lgtm

[commit-bot: I haz the power, 2015-09-07 07:18:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1331523002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1331523002/1

[commit-bot: I haz the power, 2015-09-07 08:10:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-07 08:10:43]

Patchset 1 (id:??) landed as
https://crrev.com/691f796f7297ec3076dc23a7d79bb7da7f1d10e1
Cr-Commit-Position: refs/heads/master@{#30610}