Port 043ac205

Original Commit Message:

    Implement i8x16.bitmask, i16x8.bitmask, i32x4.bitmask on x64.

R=zhin@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I1bb6439abb3db27c50e1f06a833954c473119bcd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2219007Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#68023}