Prototype the instruction on the interpreter, and Arm64. Details of
instruction lowerings on all relevant architectures can be found at:
https://github.com/WebAssembly/relaxed-simd/issues/40

Bug: v8:12284
Change-Id: Id4cb3889d94cf0bb7169ea068efe5ca68cfcbad9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3636365
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80475}