[turbofan] Port initialization of new.target variable.

[turbofan] Port initialization of new.target variable.

This implements the proper initialization of the new.target internal
variable in the AstGraphBuilder. For now this uses a runtime call that
cannot handle inlined frames correctly.

R=arv@chromium.org

Committed: https://crrev.com/e2f0bca7781bb885dc3c29c92d6d55dc9d6a91b4
Cr-Commit-Position: refs/heads/master@{#29500}

[arv (Not doing code reviews), 2015-07-06 17:54:45]

LGTM

At this point I think we are going to run into issues with deopt but I think
this step is an important incremental step.

[Michael Starzinger, 2015-07-06 18:00:59]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-07-06 18:01:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1212813008/20001

[commit-bot: I haz the power, 2015-07-06 18:02:46]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-06 18:03:08]

Patchset 2 (id:??) landed as
https://crrev.com/e2f0bca7781bb885dc3c29c92d6d55dc9d6a91b4
Cr-Commit-Position: refs/heads/master@{#29500}