[es6] Make assignment to new.target an early ReferenceError

test/message/new-target-for-loop.js

Index: test/message/new-target-for-loop.js
diff --git a/test/message/export-duplicate.js b/test/message/new-target-for-loop.js
similarity index 70%
copy from test/message/export-duplicate.js
copy to test/message/new-target-for-loop.js
index f45aefe13f8a427bd7ad5bced7da24db32ec5e25..76a8eecba22967a400ae35773f763fe596300f2c 100644
--- a/test/message/export-duplicate.js
+++ b/test/message/new-target-for-loop.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// MODULE
+// Flags: --harmony-new-target
 
-var a, b;
-export { a };
-export { a, b };
+function f() { for (new.target in {}); }