Create two versions of StoreElement: One for RawPtrT and the other one
for FixedArrayBase. They have some common code, but the FixedArrayBase
one has more cases that it allows. This can be simplified if/when we
have access to "if constexpr".

Bug: v8:6949, v8:11074
Change-Id: Ifa12fb0688f41c77fa7ec26749c5f725169faace
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2521149
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71007}