better const folding for int and bool #668

Job	Run time
Android (ubuntu-24.04, aarch64-linux-android)	8m 12s
Test (macOS-latest)	9m 59s
Compiletest (ubuntu-24.04)	8m 13s
Test (ubuntu-24.04)	8m 1s
Compiletest (windows-2022)	15m 51s
Test (windows-2022)	15m 8s
Difftest (ubuntu-24.04)	10m 22s
Compiletest (macOS-latest)	9m 54s
Difftest (windows-2022)	17m 2s
cargo-deny	1m 7s
Lint	6m 7s
Difftest (macOS-latest)	10m 28s
test_success	5s
	2h 0m 29s

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