This adds support for inline allocation of {JSFunction} objects as part
of closures instantiation for {JSCreateClosure} nodes. The lowering is
limited to instantiation sites which have already seen more than one
previous instantiation, this avoids the need to increment the respective
counter.

R=jarin@chromium.org

Change-Id: I462c557453fe58bc5f09020a3d5ebdf11c2ea68b
Reviewed-on: https://chromium-review.googlesource.com/594287
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48176}