Add copyright header to generated analyzer files.

pkg/analyzer/test/generated/test_support.dart

+// Copyright (c) 2014, 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.
+
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.test_support;
 
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_junit.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/scanner.dart';
@@ skipping 855 matching lines @@
         return trampoline(target, arguments[0], arguments[1]);
       case 3:
         return trampoline(target, arguments[0], arguments[1], arguments[2]);
       case 4:
         return trampoline(target, arguments[0], arguments[1], arguments[2], arguments[3]);
       default:
         throw new IllegalArgumentException("Not implemented for > 4 arguments");
     }
   }
 }