enabling `-gsource-map` disables JS whitespace minification

[jmcclellan-figma]

Due to logic here, it seems like linking with -gsource-map will automatically disable whitespace minification for the js file - this was a bit surprising to me because I wanted source maps for my wasm file while still having whitespace removed from my js file.

[kripken]

Yes, I think atm -gsource-map enables some amount of "debug" stuff. See #20462 for some thoughts about changing that.