Most register and immediate inputs are 5 bits long and 0x1f is used
as mask. Some immediates are byte sized in which case 0xff had to
be used.

Change-Id: Id7568732db9141743c839a2d1d21a27983547aba
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3009811Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#75644}