Tests

[mypyc] Enable assertions in tests and fix failures #20063

Job	Run time
Test mypyc suite with 32-bit Python	9m 22s
Test suite with py310-ubuntu, mypyc-compiled	15m 16s
Test suite with py314t-ubuntu, mypyc-compiled	17m 55s
Test suite with py312-ubuntu	9m 55s
Test suite with py314-ubuntu, mypyc-compiled	14m 44s
Test suite with py314-windows-64	27m 14s
Test suite with py313-ubuntu, mypyc-compiled	14m 56s
mypyc runtime tests with py313-macos	6m 47s
Test suite with py311-ubuntu	9m 53s
Parallel tests with py314-ubuntu, mypyc-compiled	29m 33s
Type check our own code (py310-ubuntu)	1m 41s
Parallel tests with py314-ubuntu, interpreted	22m 7s
mypyc runtime tests with py310-ubuntu	5m 25s
Formatting and code style with Black + ruff	1m 53s
Type check our own code (py310-windows-64)	2m 21s
	3h 9m 2s

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