No implementation needed, since relaxed swizzle is already handled in
wasm-compiler, and is visited by VisitI8x16Swizzle, and on arm64 we
generate the same code (TBL).

Bug: v8:12284
Change-Id: I446632101de26bb2f28c3f3ed60f209e81600dec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3272643Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78026}