Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_ProcessingInstructionWrappingImplementation.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 _ProcessingInstructionWrappingImplementation extends _NodeWrappingImplementation implements ProcessingInstruction {
-  _ProcessingInstructionWrappingImplementation() : super() {}
-
-  static create__ProcessingInstructionWrappingImplementation() native {
-    return new _ProcessingInstructionWrappingImplementation();
-  }
-
-  String get data() { return _get_data(this); }
-  static String _get_data(var _this) native;
-
-  void set data(String value) { _set_data(this, value); }
-  static void _set_data(var _this, String value) native;
-
-  StyleSheet get sheet() { return _get_sheet(this); }
-  static StyleSheet _get_sheet(var _this) native;
-
-  String get target() { return _get_target(this); }
-  static String _get_target(var _this) native;
-
-  String get typeName() { return "ProcessingInstruction"; }
-}