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/exposed/protected.kt

@@ -0,0 +1,20 @@
+open class A {
+    // protected relative to A
+    protected open class B { 
+        fun foo() {}
+    }
+    public open class C {
+        // protected relative to C, must be an error
+        protected open class D : <!EXPOSED_SUPER_CLASS!>B()<!>
+    }
+}
+
+class E : A.C() {
+    // F has invisible grandparent class B (E does not inherit from A)
+    class F : <!EXPOSED_SUPER_CLASS!>A.C.D()<!> {
+        init {
+            // Invoke function from invisible grandparent
+            foo() 
+        }
+    }
+}