Speedup `Uint::shr` #2009

Job	Run time
minimal-versions	28s
build (1.83.0, thumbv7em-none-eabi)	1m 52s
cross (aarch64-unknown-linux-gnu, stable)	1m 48s
build (1.83.0, wasm32-unknown-unknown)	1m 39s
cross (powerpc-unknown-linux-gnu, stable)	1m 52s
test (i686-unknown-linux-gnu, 1.83.0, sudo apt update && sudo apt install gcc-multilib)	1m 6s
build (stable, thumbv7em-none-eabi)	1m 48s
build-benchmarks	41s
test (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	1m 1s
build (stable, wasm32-unknown-unknown)	1m 34s
careful	1m 38s
test (x86_64-unknown-linux-gnu, 1.83.0)	59s
clippy	13s
test (x86_64-unknown-linux-gnu, stable)	51s
doc	25s
miri (x86_64-unknown-linux-gnu)	6m 29s
rustfmt	5s
miri (s390x-unknown-linux-gnu)	6m 37s
	31m 6s

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