Add support for spec #12420

Job	Run time
Test suite with py38-ubuntu, mypyc-compiled	1m 20s
Test mypyc suite with 32-bit Python	7m 25s
Test suite with py38-windows-64	12m 49s
Test suite with py39-ubuntu	13m 2s
Test suite with py310-ubuntu	13m 4s
Test suite with py311-ubuntu, mypyc-compiled	1m 2s
Test suite with py312-ubuntu, mypyc-compiled	1m 12s
mypyc runtime tests with py39-macos	4m 16s
mypyc runtime tests with py38-debug-build-ubuntu	4m 41s
Type check our own code (py38-ubuntu)	1m 44s
Type check our own code (py38-windows-64)	2m 16s
Formatting and code style with Black + ruff	38s
	1h 3m 29s

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