i18n.js was not using original functions

test/mjsunit/string-normalize.js

Index: test/mjsunit/string-normalize.js
diff --git a/test/mjsunit/string-normalize.js b/test/mjsunit/string-normalize.js
new file mode 100644
index 0000000000000000000000000000000000000000..f88f193a091fbab46d15685cf10ea755a7f501fd
--- /dev/null
+++ b/test/mjsunit/string-normalize.js
@@ -0,0 +1,11 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+assertEquals('', ''.normalize());
+assertTrue(delete Array.prototype.indexOf);
+assertEquals('', ''.normalize());
+
+assertThrows(function() { ''.normalize('invalid'); }, RangeError);
+assertTrue(delete Array.prototype.join);
+assertThrows(function() { ''.normalize('invalid'); }, RangeError);