[turbofan] Run DeadCodeElimination as part of the generic lowering phase.

[turbofan] Run DeadCodeElimination as part of the generic lowering phase.

This way we don't need the separate late control reduction pass over the
graph, plus we can also reduce dead code recognized by generic lowering.

R=jarin@chromium.org

Committed: https://crrev.com/94a0bc8e90830dd474d9a7405c2db66cfde30df9
Cr-Commit-Position: refs/heads/master@{#29174}

[Benedikt Meurer, 2015-06-22 06:33:17]

Hey Jaro,

First steps towards running DeadCodeElimination as part of the normal
reductions. Please take a look.

Thanks,
Benedikt

[Jarin, 2015-06-22 06:52:31]

lgtm

[Benedikt Meurer, 2015-06-22 06:52:45]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-06-22 06:52:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1198923002/1

[commit-bot: I haz the power, 2015-06-22 07:04:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-22 07:04:29]

Patchset 1 (id:??) landed as
https://crrev.com/94a0bc8e90830dd474d9a7405c2db66cfde30df9
Cr-Commit-Position: refs/heads/master@{#29174}