Port 12ecb4f5

Original Commit Message:

    No functional changes.

    - Removed unused Isolate* argument from regexp extrefs.
    - Added const where possible.
    - Removed unused functions.
    - Shuffled declarations for better readability.
    - ...

R=jgruber@chromium.org, joransiu@ca.ibm.com, junyan@redhat.com, midawson@redhat.com
BUG=
LOG=N

Change-Id: I58f21f9f75a7c7bb592b7b07dedd9c32ae8a270c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3216034Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#77359}