Rust

Move the Env testutil internal types into a single type #3843

Job	Run time
check-git-rev-deps	6s
cargo-deny (advisories)	4m 57s
rust-analyzer-compat	2m 7s
cargo-deny (bans licenses sources)	4m 41s
fmt	7s
semver-checks	3m 59s
build-and-test (msrv, ubuntu-latest, x86_64-unknown-linux-gnu)	4m 18s
build-fuzz	35s
build-and-test (msrv, ubuntu-latest, aarch64-unknown-linux-gnu, true)	2m 3s
docs	2m 1s
publish-dry-run	0s
build-and-test (msrv, macos-latest, x86_64-apple-darwin)	14m 7s
build-and-test (msrv, macos-latest, aarch64-apple-darwin)	9m 19s
readme	30s
build-and-test (msrv, windows-latest, x86_64-pc-windows-msvc)	14m 25s
build-and-test (latest, ubuntu-latest, x86_64-unknown-linux-gnu)	4m 8s
build-and-test (latest, ubuntu-latest, aarch64-unknown-linux-gnu, true)	2m 3s
build-and-test (latest, macos-latest, x86_64-apple-darwin)	13m 46s
build-and-test (latest, macos-latest, aarch64-apple-darwin)	9m 3s
build-and-test (latest, windows-latest, x86_64-pc-windows-msvc)	13m 21s
complete	1s
	1h 45m 37s

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