feat: gyp add OS `wasm` alias #1000

Job	Run time
Build (wasm32-unknown-emscripten)	5m 23s
Build (wasm64-unknown-emscripten)	7m 20s
Build (wasm32-unknown-unknown)	2m 50s
Build (wasm32-wasi)	2m 52s
Build (wasm32-wasi-threads)	4m 17s
Release	0s
	22m 42s

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