Fix spread array inside array literal

test/mjsunit/harmony/regress/regress-4298.js

Index: test/mjsunit/harmony/regress/regress-4298.js
diff --git a/test/message/formal-parameters-trailing-comma.js b/test/mjsunit/harmony/regress/regress-4298.js
similarity index 75%
copy from test/message/formal-parameters-trailing-comma.js
copy to test/mjsunit/harmony/regress/regress-4298.js
index 09cdb8904bee73012d9c53efaceff8e892666c15..c4fe5191382114f7c4caf5aa93879fa1f83b407a 100644
--- a/test/message/formal-parameters-trailing-comma.js
+++ b/test/mjsunit/harmony/regress/regress-4298.js
@@ -2,4 +2,5 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-function foo(b, a, a,) { return a }
+var arr = [1, 2, ...[3]];
+assertEquals([1, 2, 3], arr);