Before:
  488bd6 REX.W movq rdx, rsi

After:
  8bd6 movl rdx, rsi

This CL can save a 1-byte encoding length for move instruction.

Change-Id: Ief482b4093f22ab810dbc693e8d9ed55a8c14c84
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3875397
Commit-Queue: Jialu Zhang <jialu.zhang@intel.com>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83070}