Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_XMLSerializerWrappingImplementation.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.
-
-// WARNING: Do not edit - generated code.
-
-class _XMLSerializerWrappingImplementation extends DOMWrapperBase implements XMLSerializer {
-  _XMLSerializerWrappingImplementation() : super() {}
-
-  static create__XMLSerializerWrappingImplementation() native {
-    return new _XMLSerializerWrappingImplementation();
-  }
-
-  String serializeToString(Node node) {
-    return _serializeToString(this, node);
-  }
-  static String _serializeToString(receiver, node) native;
-
-  String get typeName() { return "XMLSerializer"; }
-}