Use the Operand overload of Cmp to avoid loading the object map into a
temporary in CheckMaps; this also avoids uncompressing the map pointer
when loading it.

It does mean that the migration path of CheckMapsWithMigration has to
re-load the map, and heavier use of the scratch register in that
implementation, but it's a deferred path so that should be ok.

Bug: v8:7700
Change-Id: I6741d5b5a8ad402bdef9025c43a86aca21db050e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3762574
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81719}