added emsdk and build script #334

Job	Run time
test-wasm (3.1.45)	7m 58s
test-unix (ubuntu-20.04, static_build)	2m 28s
test-unix (ubuntu-20.04, shared_build)	2m 47s
test-win (windows-2019, static_build)	5m 10s
test-unix (ubuntu-22.04, static_build)	1m 29s
test-win (windows-2019, shared_build)	6m 4s
test-unix (ubuntu-22.04, shared_build)	1m 30s
test-win (windows-2022, static_build)	5m 52s
test-unix (macos-11, static_build)	4m 0s
test-win (windows-2022, shared_build)	3m 55s
test-unix (macos-11, shared_build)	4m 4s
test-unix (macos-12, static_build)	2m 46s
test-unix (macos-12, shared_build)	3m 40s
	51m 43s

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