mypy

gh-142598: Add new type of executable to support external JITs #19229

Job	Run time
Run mypy on Lib/test/libregrtest	50s
Run mypy on Tools/check-c-api-docs	21s
Run mypy on Tools/jit	20s
Run mypy on Tools/cases_generator	19s
Run mypy on Tools/clinic	18s
Run mypy on Lib/tomllib	18s
Run mypy on Lib/_pyrepl	21s
Run mypy on Tools/peg_generator	21s
Run mypy on Tools/build	20s
	3m 28s

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