Code sequence from https://github.com/WebAssembly/simd/pull/379, and
exactly the same as x64, with minor tweaks for
ExternalReferenceAsOperand.

Bug: v8:11002
Change-Id: Icbfdac62b21c2734ad4886b3d48f34e29f7a8222
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2664860
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72495}