Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_DOMExceptionWrappingImplementation.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 _DOMExceptionWrappingImplementation extends DOMWrapperBase implements DOMException {
-  _DOMExceptionWrappingImplementation() : super() {}
-
-  static create__DOMExceptionWrappingImplementation() native {
-    return new _DOMExceptionWrappingImplementation();
-  }
-
-  int get code() { return _get_code(this); }
-  static int _get_code(var _this) native;
-
-  String get message() { return _get_message(this); }
-  static String _get_message(var _this) native;
-
-  String get name() { return _get_name(this); }
-  static String _get_name(var _this) native;
-
-  String toString() {
-    return _toString(this);
-  }
-  static String _toString(receiver) native;
-
-  String get typeName() { return "DOMException"; }
-}