This CL prepares the LiftoffAssembler interface for uintptr_t offsets.
Many places can still only handle 32-bit values, but after this CL we can
start storing the offsets as uintptr_t in the memory access immediates.
Some TODOs are placed to extend code generation for 64-bit additions, if
memory64 is enabled.
All of this will be addressed in follow-up CLs.

R=manoskouk@chromium.org

Bug: v8:10949
Change-Id: Id3b9b8aa555ab41f082ba012f4f8d80586c35b89
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2529452
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71236}