[turbofan] Add new JSFrameSpecialization reducer.

[turbofan] Add new JSFrameSpecialization reducer.

The JSFrameSpecialization specializes an OSR graph to the current
unoptimized frame on which we will perform the on-stack replacement.
This is used for asm.js functions, where we cannot reuse the OSR code
object anyway because of context specialization, and so we could as well
specialize to the max instead.

It works by replacing all OsrValues in the graph with their values in
the JavaScriptFrame.

The idea is that using this trick we get better performance without
doing the unsound backpropagation of types to OsrValues later. This is
the first step towards fixing OSR for TurboFan.

R=jarin@chromium.org
BUG=v8:4273
LOG=n

Committed: https://crrev.com/b0a852e8c2ce2add1ba8a26d572aff39af0968a3
Cr-Commit-Position: refs/heads/master@{#29476}

[Benedikt Meurer, 2015-07-06 07:02:12]

Hey Jaro,

First step for OSR fixup. Just adds the additional specialization as discussed
offline. Next steps will be followup CLs.
Please take a look.

Thanks,
Benedikt

[Jarin, 2015-07-06 07:20:18]

lgtm

[Jarin, 2015-07-06 07:20:31]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2015-07-06 07:20:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1225683004/1

[Jarin, 2015-07-06 07:22:24]

The CQ bit was unchecked by jarin@chromium.org

[Benedikt Meurer, 2015-07-06 07:45:08]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2015-07-06 07:45:08]

The patchset sent to the CQ was uploaded after l-g-t-m from jarin@chromium.org
Link to the patchset: https://codereview.chromium.org/1225683004/#ps20001
(title: "Also specialize Parameters as discussed with Jaro.")

[commit-bot: I haz the power, 2015-07-06 07:45:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1225683004/20001

[commit-bot: I haz the power, 2015-07-06 08:27:07]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-06 08:27:21]

Patchset 2 (id:??) landed as
https://crrev.com/b0a852e8c2ce2add1ba8a26d572aff39af0968a3
Cr-Commit-Position: refs/heads/master@{#29476}