This adds a new CheckIf operator and changes all direct uses of
DeoptimizeIf and DeoptimizeUnless on the JavaScript level to use
CheckIf (or one of the more concrete check operators) instead.
This way we do not depend on particular frame states, but the
effect/control linearizer will assign an appropriate frame
state instead.

R=jarin@chromium.org
BUG=v8:5141

Review-Url: https://codereview.chromium.org/2115513002
Cr-Commit-Position: refs/heads/master@{#37423}