KJS: fix refering to native nested class

js/js.translator/testData/box/inheritance/formNestedNativeClass.kt

@@ -0,0 +1,28 @@
+// FILE: foo.kt
+
+package foo
+
+@native
+class A {
+    open class B {
+        fun foo(): String
+    }
+}
+
+class C : A.B()
+
+fun box(): String {
+    return C().foo()
+}
+
+// FILE: bar.js
+
+function A() {
+}
+
+A.B = function() {
+};
+
+A.B.prototype.foo = function() {
+    return "OK"
+};