mypy

gh-127146: Fix Emscripten build with --pydebug (#131672) #13238

Job	Run time
Run mypy on Lib/_pyrepl	14s
Run mypy on Lib/test/libregrtest	14s
Run mypy on Tools/build	14s
Run mypy on Tools/cases_generator	14s
Run mypy on Tools/clinic	13s
Run mypy on Tools/jit	14s
Run mypy on Tools/peg_generator	18s
Run mypy on Tools/wasm	12s
	1m 53s

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