Variable-time modular inversion support #1956

Job	Run time
clippy	18s
build (1.83.0, thumbv7em-none-eabi)	45s
careful	1m 40s
build-benchmarks	49s
build (1.83.0, wasm32-unknown-unknown)	41s
cross (aarch64-unknown-linux-gnu, stable)	3m 39s
build (stable, thumbv7em-none-eabi)	46s
doc	30s
cross (powerpc-unknown-linux-gnu, stable)	5m 21s
build (stable, wasm32-unknown-unknown)	41s
minimal-versions	33s
miri (x86_64-unknown-linux-gnu)	4m 17s
rustfmt	12s
miri (s390x-unknown-linux-gnu)	4m 28s
test (i686-unknown-linux-gnu, 1.83.0, sudo apt update && sudo apt install gcc-multilib)	2m 29s
test (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	2m 26s
test (x86_64-unknown-linux-gnu, 1.83.0)	1m 51s
test (x86_64-unknown-linux-gnu, stable)	1m 54s
	33m 20s

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