Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_HTMLHeadingElementWrappingImplementation.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 _HTMLHeadingElementWrappingImplementation extends _HTMLElementWrappingImplementation implements HTMLHeadingElement {
-  _HTMLHeadingElementWrappingImplementation() : super() {}
-
-  static create__HTMLHeadingElementWrappingImplementation() native {
-    return new _HTMLHeadingElementWrappingImplementation();
-  }
-
-  String get align() { return _get_align(this); }
-  static String _get_align(var _this) native;
-
-  void set align(String value) { _set_align(this, value); }
-  static void _set_align(var _this, String value) native;
-
-  String get typeName() { return "HTMLHeadingElement"; }
-}