This CL also introduces/updates DCHECKs that some methods are never
reached with MinorMC (they may still be reached by full GC when MinorMC
is disabled).

Bug: v8:12612
Change-Id: I8afb8c964bc5c44225a92d0f8d9ac5a4c0ecef75
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3823130Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82439}