Simplify per-platform package exclusion in CI. (#591) #1624

Job	Run time
formatting	22s
cargo test (windows-latest)	1m 31s
cargo test (macos-latest)	40s
cargo check (msrv) (wasm32)	28s
cargo check (msrv) (windows-latest)	59s
cargo test (ubuntu-latest)	36s
cargo clippy (windows-latest)	2m 1s
cargo check (msrv) (macos-latest)	31s
cargo clippy (wasm32)	53s
cargo clippy (macos-latest)	49s
cargo check (msrv) (ubuntu-latest)	37s
compare snapshots (windows-latest)	1m 17s
cargo clippy (ubuntu-latest)	1m 26s
compare snapshots (macos-latest)	23s
cargo doc (windows-latest)	1m 20s
compare snapshots (ubuntu-latest)	33s
cargo test (wasm32)	29s
cargo doc (macos-latest)	1m 1s
typos	6s
cargo doc (ubuntu-latest)	1m 25s
	17m 27s

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