During map updating, store the pointer to new map in the
raw_transitions slot of the old map that is deprecated from map
transition tree. Thus, we can get the migration target directly
instead of TryReplayPropertyTransitions when updating map.

This can improve Speedometer2.0 Elm-TodoMVC case by ~5% on ATOM
Chromebook and ~9% on big-core Ubuntu.

Change-Id: I56f9ce5183bbdd567b964890f623ef0ceed9b7db
Reviewed-on: https://chromium-review.googlesource.com/1233433
Commit-Queue: Shiyu Zhang <shiyu.zhang@intel.com>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56303}