[cleanup] Rename CompilerDispatcher

We would like to use the name CompilerDispatcher for dispatcher base
class to be used by Sparkplug and OptimizingCompileDispatcher.

Bug: v8:12054
Change-Id: Id69955101c1f46fc2f79b6f77b05c92ed8a31edb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3077150


Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76136}