Speedup `Uint::shr` #2008

Job	Run time
clippy	20s
careful	1m 37s
build-benchmarks	25s
build (1.83.0, thumbv7em-none-eabi)	1m 55s
build (1.83.0, wasm32-unknown-unknown)	1m 44s
cross (aarch64-unknown-linux-gnu, stable)	1m 51s
doc	29s
build (stable, thumbv7em-none-eabi)	1m 46s
minimal-versions	33s
cross (powerpc-unknown-linux-gnu, stable)	1m 45s
build (stable, wasm32-unknown-unknown)	1m 38s
miri (x86_64-unknown-linux-gnu)	6m 36s
rustfmt	6s
test (i686-unknown-linux-gnu, 1.83.0, sudo apt update && sudo apt install gcc-multilib)	1m 7s
miri (s390x-unknown-linux-gnu)	6m 33s
test (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	1m 8s
test (x86_64-unknown-linux-gnu, 1.83.0)	1m 1s
test (x86_64-unknown-linux-gnu, stable)	52s
	31m 26s

Provide feedback