Enable compiling mjsunit tests as ES6 modules

test/mjsunit/harmony/modules.js

Index: test/mjsunit/harmony/modules.js
diff --git a/test/mjsunit/regress/regress-crbug-450642.js b/test/mjsunit/harmony/modules.js
similarity index 73%
copy from test/mjsunit/regress/regress-crbug-450642.js
copy to test/mjsunit/harmony/modules.js
index 7f821e0ffc0cba83ca4544d9b61041e49d97d90e..e56880500ba359914bbdd7223b43335eac3cc038 100644
--- a/test/mjsunit/regress/regress-crbug-450642.js
+++ b/test/mjsunit/harmony/modules.js
@@ -1,5 +1,8 @@
 // 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.
+//
+// MODULE
 
-assertThrows(function() { with (undefined) {} }, TypeError);
+export let a = 42;
+assertEquals(42, a);