Creating a PatchingAssembler has significant overhead, including a
dynamic allocation for the assembler buffer implementation. In the case
of {Assembler::bind} we just need it to overwrite a machine word. Hence
avoid creating the PatchingAssembler for this trivial work and just use
Memcpy directly.

R=jkummerow@chromium.org

Change-Id: I83510cfd7ebdb0d0c378df548b442eabf3727aeb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2668827Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72523}