Migrate most tests to the module system #1530

Job	Run time
JS API \| Pure JS \| Browser	1m 17s
Language \| Dart Sass \| Dart stable	58s
JS API \| Pure JS \| Node lts/* \| ubuntu-latest	1m 11s
Language \| Dart Sass \| Dart dev	1m 1s
JS API \| Embedded \| Node lts/* \| ubuntu-latest	4m 27s
JS API \| Pure JS \| Node lts/* \| windows-latest	3m 4s
Lint spec files	14s
JS API \| Embedded \| Node lts/* \| windows-latest	7m 5s
JS API \| Pure JS \| Node lts/* \| macos-latest	1m 11s
JS API \| Embedded \| Node lts/* \| macos-latest	3m 26s
Static analysis	16s
JS API \| Pure JS \| Node lts/-1 \| ubuntu-latest	1m 19s
Unit tests	38s
JS API \| Embedded \| Node lts/-1 \| ubuntu-latest	4m 40s
JS API \| Pure JS \| Node lts/-2 \| ubuntu-latest	1m 15s
JS API \| Embedded \| Node lts/-2 \| ubuntu-latest	4m 53s
JS API \| Pure JS \| Node lts/-3 \| ubuntu-latest	1m 20s
JS API \| Embedded \| Node lts/-3 \| ubuntu-latest	4m 58s
	43m 13s

Provide feedback