Add copyright header to generated analyzer files.

pkg/analyzer/lib/src/generated/constant.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.constant;
 
 import 'java_core.dart';
 import 'java_engine.dart' show ObjectUtilities;
 import 'source.dart' show Source;
 import 'error.dart' show AnalysisError, ErrorCode, CompileTimeErrorCode;
 import 'scanner.dart' show Token, TokenType;
@@ skipping 4135 matching lines @@
     }
     return BoolState.FALSE_STATE;
   }
 
   String get typeName => "Type";
 
   int get hashCode => _element == null ? 0 : _element.hashCode;
 
   String toString() => _element == null ? "-unknown-" : _element.name;
 }