[turbofan] Add support for elements kind transitions.

[turbofan] Add support for elements kind transitions.

Extend the ElementAccessInfo machinery with support for elements kind
transitions, which can be either in-place updates of the map (i.e. when
going from FAST_SMI_ELEMENTS to FAST_ELEMENTS) or instance migrations
utilizing the TransitionElementsKindStub.

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

Committed: https://crrev.com/56791805769fc473d0418dd56effa2a01c31b188
Cr-Commit-Position: refs/heads/master@{#32003}

[Benedikt Meurer, 2015-11-16 08:24:56]

Hey Jaro,

Here's the initial CL for the elements kind transitions.
Please take a look.

thanks,
Benedikt

[Jarin, 2015-11-16 08:59:07]

lgtm. I know I repeat myself, but these methods are monsters. We should think
about refactoring them.

[Jarin, 2015-11-16 08:59:11]

lgtm. I know I repeat myself, but these methods are monsters. We should think
about refactoring them.

[Benedikt Meurer, 2015-11-16 10:13:48]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-11-16 10:14:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1452563002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1452563002/1

[commit-bot: I haz the power, 2015-11-16 10:15:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-16 10:16:11]

Patchset 1 (id:??) landed as
https://crrev.com/56791805769fc473d0418dd56effa2a01c31b188
Cr-Commit-Position: refs/heads/master@{#32003}