Drive-by: Pointer to reference conversions and other smaller cleanups.

Change-Id: I83ed114e4b27d5986a389a9753333716b0e20524
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3133146Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76615}