PPC: Crankshaft is now able to compile top level code even if there is a ScriptContext.

PPC: Crankshaft is now able to compile top level code even if there is a ScriptContext.

Port 29ebcc32052d486cbc1933ac4738aa5cb68aa851

Original commit message:
    This CL introduces HPrologue instruction which does the context allocation work and supports deoptimization.

R=ishell@chromium.org, jyan@ca.ibm.com, dstence@us.ibm.com, joransiu@ca.ibm.com
BUG=

Committed: https://crrev.com/e7027442dcbdbff6d891ffc87ec4ffbf246f721f
Cr-Commit-Position: refs/heads/master@{#30516}

[dstence, 2015-09-01 15:48:42]

lgtm

[MTBrandyberry, 2015-09-01 15:53:12]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-09-01 15:53:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1324023002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1324023002/1

[commit-bot: I haz the power, 2015-09-01 16:18:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-01 16:18:36]

Patchset 1 (id:??) landed as
https://crrev.com/e7027442dcbdbff6d891ffc87ec4ffbf246f721f
Cr-Commit-Position: refs/heads/master@{#30516}