cmov: expand slice impls and tests (#1372) #1142

Job	Run time
x86 (x86_64-unknown-linux-gnu, stable)	22s
x86 (x86_64-unknown-linux-gnu, 1.85.0)	21s
test-derive (1.85.0)	25s
cross (aarch64-unknown-linux-gnu, 1.85.0)	41s
cross (powerpc-unknown-linux-gnu, stable)	51s
test-derive (stable)	19s
cross (aarch64-unknown-linux-gnu, stable)	37s
cross (powerpc-unknown-linux-gnu, 1.85.0)	1m 10s
build (stable, armv7a-none-eabi)	11s
build (stable, wasm32-unknown-unknown)	11s
build (1.85.0, thumbv7em-none-eabi)	48s
build (1.85.0, wasm32-unknown-unknown)	15s
test (x86_64-apple-darwin, macos-latest, 1.85.0)	29s
build (stable, thumbv7em-none-eabi)	13s
minimal-versions / minimal-versions	54s
test (x86_64-unknown-linux-gnu, ubuntu-latest, stable)	15s
test (i686-unknown-linux-gnu, ubuntu-latest, 1.85.0, sudo apt update && sudo apt install gcc-mult...	40s
test (x86_64-unknown-linux-gnu, ubuntu-latest, 1.85.0)	44s
test (i686-unknown-linux-gnu, ubuntu-latest, stable, sudo apt update && sudo apt install gcc-mult...	33s
build (1.85.0, armv7a-none-eabi)	15s
test (x86_64-pc-windows-msvc, windows-latest, 1.85.0)	33s
test (x86_64-pc-windows-msvc, windows-latest, stable)	46s
test (x86_64-apple-darwin, macos-latest, stable)	22s
	11m 55s

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