Port 01b8b3e0

Original Commit Message:

    This is merged into the proposal, move it out of post-mvp flags, and
    remove any ifdefs guarding it.

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

Change-Id: I366adf8f688edbc0ab39543de576f03d4cd979b3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2480602Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#70579}