Consolidate IDL test cases (15%: 34 => 29)

Source/bindings/tests/idls/TestImplements3.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
     ImplementedInBaseClass, // Conflicts with default implements class name and [ImplementedAs]
-    NoInterfaceObject,
+    NoInterfaceObject, // Always used on target of 'implements'
 ] interface TestImplements3 {
     attribute DOMString implements3StringAttribute;
     static attribute DOMString implements3StaticStringAttribute;
     void implements3VoidMethod();
     static void implements3StaticVoidMethod();
 };