This adds constant field tracking for arrays. To prevent changing the
field in some other elements-kind-branch of transition tree, we only
use the const information in the optimizing compiler if the map is not
an array map or if the map is stable (since stable maps cannot
transition to a different elements-kind-branch without deopt).

Some more details:
https://docs.google.com/document/d/1r2GAvdi_wudDS6iRUfdPw0gxWMfV-IX1PqKgwW47FyE

Bug: chromium:912162, v8:8361
Change-Id: Iea1b2f03ddee16205c2141ac5e813a973dd23cf4
Reviewed-on: https://chromium-review.googlesource.com/c/1454606
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59409}