Checks if the machine is running on a native BE and if so
try to do the load/store ops using the new vector instructions
form z15.

If target machine is older than a z15, the memory offset is larger
than 12 bits or we are running in the simulator then we fall back
to the scalar method of loading/store from memory.

Change-Id: Iec41ad21e7f292cf5b9c4707b4951a561f3dcda4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3162247Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#76878}