Refactored checkValid with ReadOnlyState #6

Job	Run time
build (gcc, current)	3m 4s
cackle	1m 38s
build (gcc, current, --check-test-tx-meta)	2m 57s
cargo-deny (advisories)	50s
fmt	16s
build (gcc, next)	3m 3s
build (gcc, next, --check-test-tx-meta)	3m 12s
cargo-deny (bans licenses sources)	45s
rust-check-git-rev-deps	26s
build (clang, current)	3m 16s
build (clang, current, --check-test-tx-meta)	3m 11s
build (clang, next)	3m 15s
build (clang, next, --check-test-tx-meta)	4m 1s
complete	1s
	29m 55s

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