Port 5e18ab50

Original Commit Message:

    This adds support for the following instructions:
    br_on_null, ref.as_non_null, br_on_cast, i31.new

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

Change-Id: Ia234f2749e401feeaf68e6b7f0b1ba2403eaa77d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2593648Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#71774}