[turbofan] Remove the JSGraph dependency from the ControlFlowOptimizer.

[turbofan] Remove the JSGraph dependency from the ControlFlowOptimizer.

The control flow optimization should work independent of the JSGraph. We
used the JSGraph there because it was convinient, not because it was
necessary.

R=jarin@chromium.org

Committed: https://crrev.com/b77df02713c1ef03844ba339035756981a481d9a
Cr-Commit-Position: refs/heads/master@{#28674}

[Benedikt Meurer, 2015-05-28 08:48:22]

Hey Jaro,

Some minor cleanup. Please take a look.

Thanks,
Benedikt

[Jarin, 2015-05-28 08:53:19]

lgtm

[Benedikt Meurer, 2015-05-28 08:53:29]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-05-28 08:53:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1160863003/1

[commit-bot: I haz the power, 2015-05-28 09:12:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-28 09:13:13]

Patchset 1 (id:??) landed as
https://crrev.com/b77df02713c1ef03844ba339035756981a481d9a
Cr-Commit-Position: refs/heads/master@{#28674}