chacha20: `rand_core` v0.10.0-rc.4 + `set_stream()`/`get_block_pos()` change #792

Job	Run time
test (stable)	22s
build (1.85.0, thumbv7em-none-eabi)	22s
test (1.85.0)	19s
build (1.85.0, wasm32-unknown-unknown)	21s
build (stable, wasm32-unknown-unknown)	25s
build (stable, thumbv7em-none-eabi)	15s
minimal-versions	-1s
	2m 3s

Provide feedback