Exposed visibility checking, a set of exposed visibility tests, some test fixes

Effective visibility mechanism introduced.
Local is considered as public, java protected as Kotlin protected, java package private as Kotlin private.

compiler/testData/diagnostics/tests/j+k/privateFieldOverridesNothing.txt

@@ -9,8 +9,8 @@ public interface A {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public/*package*/ abstract class B : A {
-    public/*package*/ constructor B()
+public abstract class B : A {
+    public constructor B()
     private final var size: kotlin.Int
     public abstract override /*1*/ /*fake_override*/ val size: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean