KeyedStoreIC computes the expected transition to the map based on the
incoming receiver map, the index and the value that is being stored.
Since we already store the element into the object, the runtime would
have already computed these transitions and it is possible to use the
new map of the object instead of recomputing the map. Though we would
need additional checks to see the newly transitioned map is indeed
a more generic elements transition and not an unexpected transition.

Bug: v8:8394
Change-Id: If6819895e5d20dd76bb062c6064593bf3a920778
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1621937
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61743}