There were some accesses that could be specialized to Pointer
instead of Any.

Also updated the WriteBarrierKind to match. Any -> full barrier,
Pointer -> Pointer barrier, Signed -> no barrier.

There were some accesses that were not used, and therefore got deleted.

Bug: v8:9396
Change-Id: Ie249e6571080fa6e24d9022344775de679966144
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1733070Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63096}