Also fix the simulator to avoid overrating dst register
during VectorPack.

Bug: v8:10971
Change-Id: I137e3cf4f73ddfc12c50099d519668858f95ecf3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2625487Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#72051}