Now that 86 has branched, we can move bitmask into the SIMD MVP, it will
not affect the current OT. (We want any OT extension to include
bitmask.)

Bitmask was accepted into the proposal in
https://github.com/WebAssembly/simd/pull/201.

Bug: v8:10308
Change-Id: Ib61190fcea2bfc0ce7bf733086e1a81388216a59
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2378290Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69577}