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/UsingKotlinPackageDeclarations.java

@@ -1,10 +1,10 @@
-import test.TestPackage;
+package test;
 
 // Check absence of 'Static method reference via subclass warning' for kotlin usages
 public class UsingKotlinPackageDeclarations {
     public static int test() {
-        TestPackage.foo();
-        TestPackage.setBar(15);
-        return TestPackage.getBar();
+        UsingKotlinPackageDeclarationsKt.foo();
+        UsingKotlinPackageDeclarationsKt.setBar(15);
+        return UsingKotlinPackageDeclarationsKt.getBar();
     }
 }