Fix generalization with callbacks.

test/mjsunit/regress/regress-migrate-callbacks.js

Index: test/mjsunit/regress/regress-migrate-callbacks.js
diff --git a/test/mjsunit/regress/regress-347912.js b/test/mjsunit/regress/regress-migrate-callbacks.js
similarity index 61%
copy from test/mjsunit/regress/regress-347912.js
copy to test/mjsunit/regress/regress-migrate-callbacks.js
index b609e36c3d4981219abcd1c244ab46f849b2863b..b1979ea44207884d2554614c40e8cf67c753a4e8 100644
--- a/test/mjsunit/regress/regress-347912.js
+++ b/test/mjsunit/regress/regress-migrate-callbacks.js
@@ -2,9 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --allow-natives-syntax
-
-var __v_4 = {};
-__v_2 = {};
-__v_2[1024] = 0;
-%DebugPrint(__v_4);
+var o1 = {};
+o1.x = 1
+o1.y = 1.5
+var o2 = {}
+o2.x = 1.5;
+o2.__defineSetter__('y', function(v) { });
+o1.y;