fix fallback codegen on bool #3452

Job	Run time
macOS / release / homebrew-clang	5m 23s
Windows / release / msvc	25m 36s
macOS / debug / homebrew-clang	4m 22s
Windows / release / clang-cl	24m 2s
macOS / release / system-clang	5m 27s
Windows / release / llvm	26m 51s
macOS / debug / system-clang	3m 36s
Windows / debug / msvc	28m 35s
Windows / debug / clang-cl	23m 35s
Windows / debug / llvm	22m 48s
	2h 50m 15s

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