Add `--strict-bool` flag to prohib treating `bool` as `int` #12951

Job	Run time
Test suite with py38-ubuntu, mypyc-compiled	17m 2s
Test suite with py38-windows-64	19m 31s
Test mypyc suite with 32-bit Python	7m 5s
Test suite with py39-ubuntu	16m 28s
Test suite with py310-ubuntu	15m 28s
Test suite with py311-ubuntu, mypyc-compiled	15m 14s
Test suite with Python nightly	14m 19s
Test suite with py312-ubuntu, mypyc-compiled	18m 1s
mypyc runtime tests with py39-macos	6m 19s
mypyc runtime tests with py38-debug-build-ubuntu	4m 43s
Type check our own code (py38-ubuntu)	1m 44s
Type check our own code (py38-windows-64)	2m 56s
Formatting and code style with Black + ruff	39s
	2h 19m 29s

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