better const folding for int and bool #667

Job	Run time
Test (ubuntu-24.04)	8m 3s
Test (windows-2022)	15m 30s
Android (ubuntu-24.04, aarch64-linux-android)	7m 52s
cargo-deny	1m 4s
Compiletest (ubuntu-24.04)	8m 19s
Compiletest (macOS-latest)	8m 54s
Compiletest (windows-2022)	15m 45s
Test (macOS-latest)	11m 36s
Difftest (ubuntu-24.04)	10m 27s
Lint	5m 29s
Difftest (windows-2022)	17m 1s
Difftest (macOS-latest)	9m 15s
test_success	2s
	1h 59m 17s

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