P9 has vector insert and extract instructions which can be
used instead of doing memory load/stores.

Change-Id: Ida8dd6c43441f1a5c04406688f8c86a656dc63eb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2613027Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#71951}