Experiment: Use rayon when resolving glyphs #1929

Job	Run time
cargo clippy (windows-latest)	3m 14s
cargo check (msrv) (windows-latest)	1m 48s
cargo clippy (macos-latest)	1m 31s
cargo check (msrv) (wasm32)	58s
cargo check (aarch64-android)	40s
cargo clippy (ubuntu-latest)	1m 39s
cargo check (msrv) (macos-latest)	1m 5s
cargo check (msrv) (ubuntu-latest)	54s
cargo clippy (wasm32)	1m 55s
cargo doc	1m 52s
formatting	22s
Prime LFS Cache	3s
cargo test (wasm32)	47s
typos	4s
cargo test (windows-latest)	3m 42s
cargo test (macos-latest)	1m 38s
cargo test (ubuntu-latest)	4m 26s
	26m 38s

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