test rename overhaul: step 8 - language tests

tests/language/class_extends_negative_test.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // Check fails because class extends from interface.
 
 interface InterfaceA {
 
 }
 
 class ClassA extends InterfaceA {
 
 }
 
 class ClassExtendsNegativeTest {
   static testMain() {
   }
 }
 
 main() {
   ClassExtendsNegativeTest.testMain();
 }