This implements arithmetic operations on i64, as well as eqz
and conditional set for the arm32 port of Liftoff.

Bug: v8:6600
Change-Id: I21dc0f820e1429392599a5813c44b938c38093a2
Reviewed-on: https://chromium-review.googlesource.com/c/1348082
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57910}