Revert "Add Selection.toString() calling the native method"

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

Index: tools/dom/templates/html/impl/impl_Selection.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Selection.darttemplate b/tools/dom/templates/html/impl/impl_Selection.darttemplate
deleted file mode 100644
index ed9f52abefdd5a55187958812e98715aaa2dbf38..0000000000000000000000000000000000000000
--- a/tools/dom/templates/html/impl/impl_Selection.darttemplate
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright (c) 2017, 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.
-
-part of $LIBRARYNAME;
-
-$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
-$!MEMBERS
-$if DART2JS
-  @DomName('Selection.toString')
-  @DocsEditable()
-  String toString() native;
-$endif
-}