Caching nodes with mutable inputs is a bad idea and already blew up
twice now, so in order to avoid further breakage, let's kill the
EmptyFrameState caching on JSGraph completely and only cache the empty
state values there.

We can remove the hacking from JSTypedLowering completely once we have
the PlainPrimitiveToNumber in action.

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2006423003
Cr-Commit-Position: refs/heads/master@{#36511}