game_wasm.js is no longer minified

[AGulev]

Describe the bug (REQUIRED)
It seems like game_wasm.js is no longer minified after emscripten update, more info is available on forum:
https://forum.defold.com/t/defold-1-8-0-beta/76535/78?u=agulev

Defold version (REQUIRED):

• Version 1.8.0

[ekharkunov]

I researched on test project (simple .c file) and got following results:

• pass only -O3 option to emcc command produce minified result
• if add LEGACY_VM_SUPPORT or MIN_FIREFOX_VERSION=34, MIN_SAFARI_VERSION=90000, etc - result isn't minified.
• pass --closure=1 doesn't help. Result still non-minified.
  When I digging deeper I found that --closure=1 option doesn't help because closure-compiler runs before babel compiler https://github.com/emscripten-core/emscripten/blob/3.1.55/tools/link.py#L2146-L2153.
  Main problem is running babel compiler when we need to support old browser. Initially babel compiler was introduced in 3.1.51 (https://github.com/emscripten-core/emscripten/blob/main/ChangeLog.md#3151---121323).

There are two workarounds:

1. Modify emscripten code and run closure-compiler after babel compiler. It need to add additional options to waf_dynamo.py and build_input.yml
2. Add babel-preset-minify package to emscripten and modify emscripten code in following way:

cmd = shared.get_npm_cmd('babel') + [filename, '-o', outfile, '--presets', '@babel/preset-env,babel-preset-minify',  '--config-file', config_file]

Issue at emscripten project:
emscripten-core/emscripten#21881

[ekharkunov]

Fixes were made emscripten-core/emscripten#21882. Waits for official release.