Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_XPathExpressionWrappingImplementation.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 _XPathExpressionWrappingImplementation extends DOMWrapperBase implements XPathExpression {
-  _XPathExpressionWrappingImplementation() : super() {}
-
-  static create__XPathExpressionWrappingImplementation() native {
-    return new _XPathExpressionWrappingImplementation();
-  }
-
-  XPathResult evaluate(Node contextNode, int type, XPathResult inResult) {
-    return _evaluate(this, contextNode, type, inResult);
-  }
-  static XPathResult _evaluate(receiver, contextNode, type, inResult) native;
-
-  String get typeName() { return "XPathExpression"; }
-}