[turbofan] Improve interplay of ControlReducer and CommonOperatorReducer.

[turbofan] Improve interplay of ControlReducer and CommonOperatorReducer.

This turns the CommonOperatorReducer into an AdvancedReducer and makes
it independent of JSGraph (which was used only because it was convienent),
and let's the CommonOperatorReducer run together with the ControlReducer.

The ControlReducer is still not able to run together with other reducers,
but we're getting closer. The plan is to split the ControlReducer into
two parts: The dead code elimination part and the common operator
reduction part. This separation will help to avoid tricky bugs in the
future and should make testing a *lot* easier.

R=jarin@chromium.org

Committed: https://crrev.com/92e6bcf13c2c9834e1d45930a3f6442a3a0feb87
Cr-Commit-Position: refs/heads/master@{#29105}

[Benedikt Meurer, 2015-06-18 08:43:32]

Hey Jaro,

This is the first step towards dead code elimination (Dead node propagation) as
part of the other reductions. Several parts of the ControlReducer were just
mirroring functionality of the CommonOperatorReducer. These are gone now. Plus
some prepatory cleanup. Please take a look.

Thanks,
Benedikt

[Benedikt Meurer, 2015-06-18 08:53:16]

... preparation cleanup...

[Jarin, 2015-06-18 09:09:11]

lgtm

[Benedikt Meurer, 2015-06-18 09:09:42]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-06-18 09:09:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1192063002/1

[commit-bot: I haz the power, 2015-06-18 09:15:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-18 09:15:51]

Patchset 1 (id:??) landed as
https://crrev.com/92e6bcf13c2c9834e1d45930a3f6442a3a0feb87
Cr-Commit-Position: refs/heads/master@{#29105}