Tests

Fix various crahses on recursive type variable defaults #22375

Job	Run time
Test suite with py310-ubuntu, mypyc-compiled	17m 22s
Test suite with py311-ubuntu	9m 43s
Type check our own code (py310-windows-64)	2m 8s
Test suite with py315-ubuntu, mypyc-compiled	15m 58s
mypyc runtime tests with py310-ubuntu	6m 46s
Test suite with py312-ubuntu	10m 58s
Parallel tests with py314-windows-64, interpreted	11m 9s
Parallel tests with py314-ubuntu, mypyc-compiled	30m 18s
Type check our own code (py310-ubuntu)	1m 13s
Test suite with py313-ubuntu, mypyc-compiled	16m 3s
Test suite with py314-windows-64	29m 42s
mypyc runtime tests with py313-macos	6m 22s
Formatting and code style with Black + ruff	2m 1s
Test mypyc suite with 32-bit Python	11m 20s
Test suite with py314t-ubuntu, mypyc-compiled	18m 15s
Parallel tests with py314-ubuntu, interpreted	27m 6s
Test suite with py314-ubuntu, mypyc-compiled	15m 50s
	3h 52m 14s

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