Refactor register saving (both general and double registers) as using a
PushAll helper taking a RegList.

Change-Id: I0ccdec091f60988cbdb6893eb9cdda11efd8e1eb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3749176
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81580}