Add copyright header to generated analyzer files.

pkg/analyzer/lib/src/generated/sdk_io.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.sdk.io;
 
 import 'java_core.dart';
 import 'java_io.dart';
 import 'java_engine_io.dart';
 import 'source_io.dart';
 import 'error.dart';
@@ skipping 538 matching lines @@
               }
             }
           }
         }
       }
       librariesMap.setLibrary(libraryName, library);
     }
     return null;
   }
 }