This will make these functions usable from Liftoff when we later
implement extended multiply instructions in Liftoff.

This is similar to the x64 versions, except that it takes a scratch
register as a parameter.

Bug: v8:11262
Change-Id: Ief3d8cdde59da9e05a468286315bcae6d13863d9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2603768Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71907}