MODULES: lib1, lib3, lib2, main

STEP 0:
    libs: lib1, lib3, lib2, main
    dirty js: lib1, lib2, lib3, main
STEP 1:
    libs: lib1, lib3, lib2, main
    dirty js: lib1
STEP 2:
    libs: lib1, lib3, lib2, main
    dirty js: lib3