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

Review URL: https://codereview.chromium.org/1192063002

Cr-Commit-Position: refs/heads/master@{#29105}