Remove generated directories with 100s of files.

client/html/generated/html/interface/HTMLCollection.dart

Index: client/html/generated/html/interface/HTMLCollection.dart
diff --git a/client/html/generated/html/interface/HTMLCollection.dart b/client/html/generated/html/interface/HTMLCollection.dart
deleted file mode 100644
index 64ff8bb0d42af34fbd0541a14c0194fffb3e48a4..0000000000000000000000000000000000000000
--- a/client/html/generated/html/interface/HTMLCollection.dart
+++ /dev/null
@@ -1,14 +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 HTMLCollection extends List<Node> {
-
-  final int length;
-
-  Node item(int index);
-
-  Node namedItem(String name);
-}