fuzz: Add upgrade/downgrade simulation to chanmon_consistency and fix chacha20 build #22495

Job	Run time
check_release	2m 48s
build-bindings / build (self-hosted, 1.75.0)	21m 19s
tor-connect	5m 0s
benchmark	17m 23s
rustfmt	18s
build-nostd / build (self-hosted, 1.75.0)	21m 37s
linting	2m 26s
build-workspace / build (self-hosted, 1.75.0)	20m 22s
fuzz	1h 25m 49s
ext-test	6m 53s
check_docs	5m 58s
build-features / build (self-hosted, 1.75.0)	33m 48s
build-sync / build (self-hosted, 1.75.0)	26m 30s
build-cfg-flags / build (self-hosted, 1.75.0)	17m 32s
coverage	1h 2m 46s
notify-failure	-1s
	5h 30m 28s

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