Outer's superclass' method is now inaccessible from nested

Also the diagnostic error message reported the wrong nested class name: it
should be the nested class in the hierarchy which is static, not the class of
the scope where we're checking the accessibility

idea/testData/diagnosticMessage/inaccessibleOuterClassExpression.kt

@@ -0,0 +1,7 @@
+class A {
+    class B {
+        val r = object {
+            fun bar() = this@A
+        }
+    }
+}