rune: Performance improvements #1834

Job	Run time
clippy	2m 4s
docs	2m 59s
msrv	1m 30s
nightly	3m 12s
rustfmt	13s
basics	1s
test_miri (rune)	3m 20s
build_feature (alloc)	3m 19s
test_miri (rune-core)	42s
build_feature (cli)	4m 1s
test_miri (rune-alloc)	4m 1s
build_feature (cli,doc)	3m 55s
test_doc	4m 1s
no_std (ubuntu-latest, minimal)	1m 9s
build_feature (cli,fmt)	4m 0s
test_lib	4m 2s
build_feature (doc)	3m 30s
no_std (macos-latest, minimal)	1m 23s
build_feature (workspace)	3m 21s
test_rune	3m 0s
build_feature (languageserver)	3m 56s
wasm	1m 12s
build_feature (byte-code)	3m 30s
build_feature (capture-io)	3m 28s
build_feature (emit)	3m 27s
	1h 9m 16s

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