Merge PR #28229 into master

Merge PR #28229 into master

* refs/pull/28229/head:
	os/bluestore: do garbage collection if blob count is too high.
	common/perf_conters: make dump_formatted_xxx funcs as const.
	os/bluestore: store extents for GC within WriteContext.
	os/bluestore: GC class, make some members local.
	os/bluestore: vector -> interval set in GC to track extents to collect.
	tests/store_test: many-many spanning blobs test case

Reviewed-by: Sage Weil <sage@redhat.com>