Pinsrb, Pinsrw was separately defined in ia32 and x64 macro assembler,
move them into shared-macro-assembler.

Pinsrd can be moved also, but is not as straightforward, move that in a
future patch.

Bug: v8:11589
Change-Id: Ib5c7517236e0c3fb7b9a4643f0a3ee8237ee6545
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3158681Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76820}