mypy

gh-144490: Fix mimalloc debug build for C++ (#144620) #19463

Job	Run time
Run mypy on Lib/test/libregrtest	20s
Run mypy on Lib/_pyrepl	22s
Run mypy on Tools/build	22s
Run mypy on Tools/peg_generator	22s
Run mypy on Lib/tomllib	20s
Run mypy on Tools/check-c-api-docs	21s
Run mypy on Tools/jit	17s
Run mypy on Tools/cases_generator	22s
Run mypy on Tools/clinic	18s
	3m 4s

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