Sliding Sync: Speed up SS room sorting #2353

Job	Run time
lint-crlf	7s
check-lockfile	14s
changes	2s
lint-newsfile	34s
Typechecking	2m 47s
check-sampleconfig	49s
check-schema-delta	42s
lint	52s
lint-clippy	0s
lint-pydantic	1m 2s
lint-clippy-nightly	0s
lint-readme	0s
lint-rustfmt	0s
linting-done	2s
calculate-test-jobs	7s
portdb (3.8, 11)	3m 0s
trial-olddeps	7m 50s
complement (monolith, SQLite)	25m 13s
portdb (3.11, 15)	2m 51s
complement (monolith, Postgres)	13m 18s
complement (workers, Postgres)	25m 33s
trial-pypy	0s
cargo-bench	0s
cargo-test	0s
sytest (focal)	8m 33s
sytest (focal, postgres)	10m 14s
trial (3.8, sqlite, all)	4m 55s
sytest (focal, multi-postgres, workers)	14m 20s
trial (3.8, postgres, 11, all)	11m 38s
trial (3.8, sqlite)	4m 27s
sytest (focal, multi-postgres, workers, asyncio)	19m 2s
export-data	2m 10s
tests-done	2s
	2h 40m 24s

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