Most instructions need get_modrm, and it doesn't affect instructions
which don't use it, since get_modrm doesn't mess with any pointers.

Bug: v8:10933
Change-Id: I5b97d138f7e6ab78e6a72dc6fa4f0d5d0784a03f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2497296Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70770}