k256+primeorder: add `batch_normalize_generic` #147

Job	Run time
build (1.65.0, thumbv7em-none-eabi)	4m 0s
build (1.65.0, wasm32-unknown-unknown)	3m 39s
doc	29s
cross (armv7-unknown-linux-gnueabihf, 1.65.0)	5m 6s
build (stable, thumbv7em-none-eabi)	11s
test (i686-unknown-linux-gnu, 1.65.0, sudo apt update && sudo apt install gcc-multilib)	4m 50s
cross (armv7-unknown-linux-gnueabihf, stable)	1m 9s
build (stable, wasm32-unknown-unknown)	12s
test (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	1m 17s
cross (aarch64-unknown-linux-gnu, 1.65.0)	4m 56s
test (x86_64-unknown-linux-gnu, 1.65.0)	8m 9s
cross (aarch64-unknown-linux-gnu, stable)	1m 11s
test (x86_64-unknown-linux-gnu, stable)	51s
cross (powerpc-unknown-linux-gnu, 1.65.0)	5m 25s
cross (powerpc-unknown-linux-gnu, stable)	1m 26s
	42m 51s

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