Generate actual nested classes for actual owner class #KT-19937 Fixed

idea/testData/multiModuleQuickFix/sealed/js/Sealed.kt.after

@@ -1,6 +1,6 @@
 // Sealed: to be implemented
 actual sealed class Sealed {
-    object Obj : Sealed
+    actual object Obj : Sealed
+    actual class Klass(x: Int) : Sealed
 
-    class Klass(x: Int) : Sealed
 }