WebAssembly: build both the multithreaded and non-multithreaded versions in parallel, optimize the workflows a bit #13063

Job	Run time
Code style check / Code style check	7s
IWYU / IWYU	4m 11s
CodeChecker / CodeChecker	19m 39s
MSVC / MSVC (SDL2 x86)	4m 16s
SonarCloud Analyzer / SonarCloud Analyzer	0s
MSVC / MSVC (SDL2 x64)	4m 2s
CMake / CMake (Windows SDL2)	4m 25s
CMake / CMake (Linux SDL2)	3m 5s
CMake / CMake (macOS SDL2)	1m 54s
Android / Android	11m 6s
CMake / CMake (macOS SDL2 App Bundle)	1m 41s
Make / Make (Linux x86-64 SDL2 Release)	2m 30s
Make / Make (PS Vita)	8m 49s
Make / Make (Linux x86-64 SDL2 Debug)	4m 54s
Make / Make (Linux ARM64 SDL2 Release)	2m 25s
Make / Make (Nintendo Switch)	3m 13s
Make / Make (Linux ARM64 SDL2 Debug)	2m 51s
Make / Make (Emscripten)	6m 45s
Make / Make (macOS SDL2)	2m 37s
Make / Make (Emscripten Multithreaded)	6m 51s
Make / Make (macOS SDL2 App Bundle)	1m 36s
	1h 36m 57s

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