Remove (Gecko) WebIDL files that don't generate any bindings (#3726) #1586

Job	Run time
Check	1m 8s
build_benchmarks	57s
build_nightly	1m 38s
build_examples	3m 27s
Verify that web-sys is compiled correctly	54s
Clippy	5m 11s
dist_linux_aarch64_gnu	2m 46s
dist_linux_x86_64_musl	2m 38s
dist_macos_aarch64	4m 21s
dist_macos_x86_64	3m 40s
dist_windows	2m 50s
doc_api	1m 9s
doc_book	11s
Rustfmt	12s
Build and test the deno example	50s
Run js-sys crate tests	2m 16s
Run native tests	1m 46s
Run wasm-bindgen crate tests with multithreading enabled	1m 57s
Test TypeScript output of wasm-bindgen	1m 0s
Run UI compile-fail tests	4m 41s
Run wasm-bindgen crate tests (unix)	11m 34s
Run web-sys crate tests	4m 6s
Run wasm-bindgen-webidl crate tests	2m 3s
test_examples	2m 1s
deploy	1m 17s
	1h 4m 33s

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