The displacement for vlbr and vstbr is a 12-bit unsigned integer.
If a greater offset is passed we must fall back to using
lrvg and strvg.

Change-Id: I34107b82960a4d4de99fbf8b9324b13d9a455e67
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2504190Reviewed-by: Junliang Yan <junyan@redhat.com>
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#70809}