Tests

Improve match subject inference #17694

Job	Run time
Test mypyc suite with 32-bit Python	5m 25s
Test suite with py310-ubuntu	5m 22s
Test suite with py312-ubuntu, mypyc-compiled	5m 22s
Test suite with py39-ubuntu, mypyc-compiled	5m 21s
Test suite with py313-ubuntu, mypyc-compiled	5m 22s
Test suite with py311-ubuntu	5m 22s
Type check our own code (py39-windows-64)	2m 34s
Test suite with py313-windows-64	5m 17s
mypyc runtime tests with py39-macos	5m 28s
Test suite with py314-dev-ubuntu	5m 21s
Formatting and code style with Black + ruff	1m 46s
Type check our own code (py39-ubuntu)	1m 34s
	54m 14s

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