[turbofan] Fix pushing of JSToBooleans into Phis.

[turbofan] Fix pushing of JSToBooleans into Phis.

Now we actually implement it the way it is meant to be, that is:

  JSToBoolean(Phi(x1,...,xn):primitive)
    => Phi(JSToBoolean(x1),...,JSToBoolean(xn)):boolean

This also fixes the endless recursion within JSTypedLowering when
the GraphReducer does all possible reductions instead of using the
generic algorithm.

R=dcarney@chromium.org

Committed: https://chromium.googlesource.com/v8/v8/+/2eaca10e9bdc18cb1127db05613313109a374d0e

[Benedikt Meurer, 2014-11-17 11:54:23]

PTAL

[dcarney, 2014-11-17 12:03:46]

lgtm

[Benedikt Meurer, 2014-11-17 12:11:02]

Committed patchset #3 (id:40001) manually as
2eaca10e9bdc18cb1127db05613313109a374d0e (presubmit successful).