Remove duplicate test

test/built-ins/JSON/stringify/15.12.3_4-1-2.js

@@ -3,11 +3,15 @@
 
 /*---
 es5id: 15.12.3_4-1-2
-description: JSON.stringify a circular object throws a TypeError
+description: JSON.stringify a indirectly circular object throws a error
 ---*/
 
-var obj = {};
-obj.prop = obj;
+var obj = {
+  p1: {
+    p2: {}
+  }
+};
+obj.p1.p2.prop = obj;
 
 assert.throws(TypeError, function() {
   JSON.stringify(obj);

test/built-ins/JSON/stringify/15.12.3_4-1-3.js

-// Copyright (c) 2012 Ecma International.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-es5id: 15.12.3_4-1-3
-description: JSON.stringify a indirectly circular object throws a error
----*/
-
-var obj = {
-  p1: {
-    p2: {}
-  }
-};
-obj.p1.p2.prop = obj;
-
-assert.throws(TypeError, function() {
-  JSON.stringify(obj);
-});