Tests

Fix crash on Unpack used without arguments in class bases #22259

Job	Run time
Test mypyc suite with 32-bit Python	11m 34s
mypyc runtime tests with py310-ubuntu	6m 47s
Test suite with py310-ubuntu, mypyc-compiled	17m 8s
Test suite with py312-ubuntu	10m 29s
Formatting and code style with Black + ruff	1m 54s
Parallel tests with py314-windows-64, interpreted	10m 15s
mypyc runtime tests with py313-macos	6m 30s
Test suite with py315-ubuntu, mypyc-compiled	16m 13s
Test suite with py314-windows-64	31m 59s
Test suite with py311-ubuntu	9m 16s
Parallel tests with py314-ubuntu, interpreted	25m 50s
Test suite with py314-ubuntu, mypyc-compiled	16m 34s
Test suite with py314t-ubuntu, mypyc-compiled	18m 49s
Type check our own code (py310-ubuntu)	1m 14s
Parallel tests with py314-ubuntu, mypyc-compiled	29m 57s
Type check our own code (py310-windows-64)	2m 9s
Test suite with py313-ubuntu, mypyc-compiled	15m 55s
	3h 52m 33s

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