For 64-bit binary operations, Liftoff on arm made the assumption that
register pairs are always ordered, i.e. the register code for the low
word is lower than the register code for the high word.
Ensuring this was only implemented in {GetUnusedRegister} in
https://crrev.com/c/2168875. Other cases were missing though, e.g.
return values, but also different places were we
construct register pairs internally.

Thus, this CL removes this constraint again and instead handles
unordered register pairs in 64-bit binary operations on arm.

R=thibaudm@chromium.org

Bug: chromium:1101304
Change-Id: I4cd9fb1577f82ab06d34c9dde6533cf04a2cade7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2287870Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68752}