Remove MutationEvent bad entries in both removed list and renamed list

tools/dom/templates/html/impl/impl_MutationEvent.darttemplate

Index: tools/dom/templates/html/impl/impl_MutationEvent.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_MutationEvent.darttemplate b/tools/dom/templates/html/impl/impl_MutationEvent.darttemplate
deleted file mode 100644
index 550e749cbc9cc7e690e60173c4e307966fb399a2..0000000000000000000000000000000000000000
--- a/tools/dom/templates/html/impl/impl_MutationEvent.darttemplate
+++ /dev/null
@@ -1,18 +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.
-
-part of $LIBRARYNAME;
-
-$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
-  factory $CLASSNAME(String type,
-      {bool canBubble: false, bool cancelable: false, Node relatedNode,
-      String prevValue, String newValue, String attrName, int attrChange: 0}) {
-
-    _MutationEvent event = document._createEvent('MutationEvent');
-    event._initMutationEvent(type, canBubble, cancelable, relatedNode,
-        prevValue, newValue, attrName, attrChange);
-    return event;
-  }
-$!MEMBERS
-}