`registers` is only used on platforms which support sparkplug.

Bug: v8:11420
Change-Id: Ia08fb1b76194db222703a64618fc2dcb00f58c96
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2780013Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#73605}