Tests

`--strict-equality` for `None` #17741

Job	Run time
Test mypyc suite with 32-bit Python	9m 45s
Test suite with py39-ubuntu, mypyc-compiled	30m 1s
Test suite with py313-windows-64	22m 46s
Test suite with py311-ubuntu	9m 54s
Test suite with py310-ubuntu	10m 19s
Type check our own code (py39-windows-64)	2m 27s
Type check our own code (py39-ubuntu)	1m 41s
Test suite with py313-ubuntu, mypyc-compiled	12m 47s
Test suite with py314-dev-ubuntu	27m 59s
mypyc runtime tests with py39-macos	6m 50s
Test suite with py312-ubuntu, mypyc-compiled	19m 3s
Formatting and code style with Black + ruff	1m 39s
	2h 35m 11s

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