Add HeapNumber fast path to v8::Value::{Uint,Int}32Value()

Add HeapNumber fast path to v8::Value::{Uint,Int}32Value()

This has the added benefit that these functions are now guaranteed not to throw when v8::Value::Is{Uint,Int}32() returned true, even when calling into JavaScript would throw a stack limit error.

BUG=chromium:446097
LOG=y

Committed: https://crrev.com/0e11bb7b853a4d48d1231d3aa068e92677c43c05
Cr-Commit-Position: refs/heads/master@{#26273}

[Jakob Kummerow, 2015-01-26 14:38:46]

jkummerow@chromium.org changed reviewers:
+ jochen@chromium.org

[jochen (gone - plz use gerrit), 2015-01-26 14:39:21]

lgtm

[Jakob Kummerow, 2015-01-26 14:40:06]

The CQ bit was checked by jkummerow@chromium.org

[commit-bot: I haz the power, 2015-01-26 14:40:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/873983003/1

[commit-bot: I haz the power, 2015-01-26 15:08:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-26 15:08:15]

Patchset 1 (id:??) landed as
https://crrev.com/0e11bb7b853a4d48d1231d3aa068e92677c43c05
Cr-Commit-Position: refs/heads/master@{#26273}