Re-enable the creation of elements transition groups in
JSHeapBroker::ProcessFeedbackMapsForElementAccess. This turned out to be
quite important for performance.

Bug: v8:7790,v8:12031
Change-Id: I4d24837a668a5f7e78a5078212a7dc34b767d703
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3085262Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76215}