JPS JS: simplified the code and added tests for the missing meta.js case (e.g. empty sourceroot; fixed by yole in 00ed0248d9a23701dbef52da02259d174a9999e7)

jps-plugin/testData/general/KotlinJavaScriptProjectWithTestsAndTestAndSrcModuleDependency/src/Main.kt

@@ -1,3 +1,7 @@
+import src.*
+import test.*
+
 fun main() {
     srcAndTests()
+    ambiguous()
 }