[es6] re-implement rest parameters via desugaring

test/mjsunit/harmony/arrow-rest-params-lazy-parsing.js

Index: test/mjsunit/harmony/arrow-rest-params-lazy-parsing.js
diff --git a/test/mjsunit/harmony/arrow-rest-params.js b/test/mjsunit/harmony/arrow-rest-params-lazy-parsing.js
similarity index 97%
copy from test/mjsunit/harmony/arrow-rest-params.js
copy to test/mjsunit/harmony/arrow-rest-params-lazy-parsing.js
index b1e8dcc1b99b484a9257b1f3a4c73ad5c94db0e1..0ae4d7688553506946020fbe769cbb9f60d1a2de 100644
--- a/test/mjsunit/harmony/arrow-rest-params.js
+++ b/test/mjsunit/harmony/arrow-rest-params-lazy-parsing.js
@@ -1,8 +1,9 @@
-// Copyright 2014 the V8 project authors. All rights reserved.
+// Copyright 2015 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.
 
 // Flags: --harmony-rest-parameters --harmony-arrow-functions
+// Flags: --min-preparse-length=0
 
 (function testRestIndex() {
   assertEquals(5, ((...args) => args.length)(1,2,3,4,5));