tests

Replace ordered_set with dict #5212

Job	Run time
collateral (diffcov)	5m 17s
test (3.8, ubuntu-latest)	4m 12s
test_cygwin (39, windows-latest)	13m 37s
collateral (docs)	2m 9s
test (3.8, windows-latest)	11m 16s
test (3.12, ubuntu-latest)	5m 28s
test (3.12, macos-latest)	5m 25s
test (3.12, windows-latest)	12m 51s
test (3.9, ubuntu-latest)	4m 18s
test (3.10, ubuntu-latest)	4m 4s
test (3.11, ubuntu-latest)	4m 14s
test (pypy3.10, ubuntu-latest, stdlib)	15m 44s
test (ubuntu-latest, 3.10, stdlib)	4m 16s
test (3.8, macos-13)	6m 7s
integration-test	0s
check	2s
release	0s
	1h 39m 0s

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