We observed T_NONE on `cc->cme_` on a --repeat-count=50 run a compaction
test on CI:
http://ci.rvm.jp/results/trunk-repeat50@ruby-sp2-noble-docker/5654900

During reference updating for imemo_callcache in
rb_imemo_mark_and_move(), if `cc->klass` is not live, but `cc->_cme` is
live and moved, we go to the vm_cc_invalidate() path which
leaves `cc->_cme` not updated and stale. In the next marking run after
compaction, CME would've become a T_NONE.

So to quote the comment above "... cc is invalidated by
`vm_cc_invalidate()` and cc->cme is not be accessed."