Merge PR #23195 into master

* refs/pull/23195/head:
	mds: use vector for context lists
	common: make C_ContextsBase container agnostic
	common: make finish_contexts container agnostic
	mds: add vector def for MDS contexts
	mds: use compact map to manage waiting list

Reviewed-by: Zheng Yan <zyan@redhat.com>

diff --cc src/mds/MDCache.cc
Simple merge

diff --cc src/mds/Migrator.cc
Simple merge