Remove generated directories with 100s of files.

client/dom/generated/src/interface/HTMLOptGroupElement.dart

Index: client/dom/generated/src/interface/HTMLOptGroupElement.dart
diff --git a/client/dom/generated/src/interface/HTMLOptGroupElement.dart b/client/dom/generated/src/interface/HTMLOptGroupElement.dart
deleted file mode 100644
index bf895e80e755336a7491b6e891811900226301ce..0000000000000000000000000000000000000000
--- a/client/dom/generated/src/interface/HTMLOptGroupElement.dart
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright (c) 2012, 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.
-
-interface HTMLOptGroupElement extends HTMLElement {
-
-  bool disabled;
-
-  String label;
-}