Port 906b9644

Original Commit Message:

    This is merged into the proposal:
    https://github.com/WebAssembly/simd/issues/419#issuecomment-765675472.

R=zhin@chromium.org, joransiu@ca.ibm.com, junyan@redhat.com, midawson@redhat.com
BUG=
LOG=N

Change-Id: I801c4337e2ea4671ef82cb1244b8da251d56fc2f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2650242Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#72341}