Fixed DCHECK in StoreIC::CompileHandler().

test/mjsunit/regress/regress-crbug-489597.js

Index: test/mjsunit/regress/regress-crbug-489597.js
diff --git a/test/message/export-duplicate-default.js b/test/mjsunit/regress/regress-crbug-489597.js
similarity index 65%
copy from test/message/export-duplicate-default.js
copy to test/mjsunit/regress/regress-crbug-489597.js
index 72a54a45f40b3d6718b670a3cbb832154032da6d..b10af92b5f37e8264ee987a1260b7beadf7fd9ba 100644
--- a/test/message/export-duplicate-default.js
+++ b/test/mjsunit/regress/regress-crbug-489597.js
@@ -1,8 +1,12 @@
 // 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
 
-export default function f() {};
-export default class C {};
+try {
+  load("test/mjsunit/regress/regress-crbug-489597.js-script");
+} catch (e) {
+}
+
+var o = this;
+Error.captureStackTrace(o);
+o.stack;