Implement `--skip` flag in test runner #1691

Job	Run time
Run wasm-bindgen crate tests (unix)	6m 46s
Rustfmt	6s
Check	54s
build_examples	3m 12s
Verify that web-sys is compiled correctly	50s
Clippy	5m 6s
Build and test the deno example	47s
Run js-sys crate tests	2m 9s
Run native tests	1m 38s
Test TypeScript output of wasm-bindgen	1m 8s
Run UI compile-fail tests	2m 51s
Run wasm-bindgen crate tests with multithreading enabled	1m 28s
Run web-sys crate tests	3m 46s
Run wasm-bindgen-webidl crate tests	1m 55s
build_benchmarks	47s
build_nightly	1m 39s
dist_linux_aarch64_gnu	2m 42s
dist_linux_x86_64_musl	2m 16s
dist_macos_aarch64	1m 56s
dist_macos_x86_64	1m 52s
dist_windows	2m 55s
doc_api	1m 12s
doc_book	9s
test_examples	2m 19s
deploy	1m 17s
	51m 40s

Provide feedback