rune: Enable more miri tests #1805

Job	Run time
docs	3m 40s
nightly	4m 31s
msrv	1m 37s
rustfmt	12s
clippy	2m 5s
basics	1s
wasm	1m 21s
no_std (ubuntu-latest, minimal)	1m 19s
test_doc	5m 51s
build_feature (alloc)	3m 18s
test_lib	4m 14s
build_feature (cli)	3m 58s
build_feature (cli,doc)	3m 59s
test_miri (rune)	3m 38s
no_std (macos-latest, minimal)	1m 18s
test_rune	2m 58s
build_feature (cli,fmt)	3m 54s
test_miri (rune-core)	55s
test_miri (rune-alloc)	6m 0s
build_feature (doc)	3m 37s
build_feature (workspace)	3m 16s
build_feature (languageserver)	3m 46s
build_feature (byte-code)	3m 30s
build_feature (capture-io)	3m 27s
build_feature (emit)	3m 36s
	1h 16m 1s

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