Dropping package facades:

- light classes: do not generate light class for package facade
- drop package facades as multifile classes compilation mode support
- get rid of some additional package facade fqName usages
- update tests for light classes

idea/testData/kotlinAndJavaChecker/TopLevelFunctionInDataFlowInspection.java

@@ -1,11 +1,11 @@
 package test;
 
 import org.jetbrains.annotations.NotNull;
-import test.kotlin.KotlinPackage;
+import test.kotlin.*;
 
 public class TopLevelFunctionInDataFlowInspection {
     void other(@NotNull Object some) {
-        Object foo = KotlinPackage.foo(some);
+        Object foo = TopLevelFunctionInDataFlowInspectionKt.foo(some);
     }
 }