fix flaky test serializeObjectPropertyWithRequiredProperties

Author: xinying7

modules/swagger-core/src/test/java/io/swagger/v3/core/serialization/properties/PropertySerializationTest.java

@@ -327,8 +327,11 @@ public void serializeObjectPropertyWithRequiredProperties() throws IOException {
         final Schema p = new ObjectSchema()
                 .addProperties("stringProperty", new StringSchema());
         p.required(Arrays.asList("stringProperty"));
-        final String json = "{\"required\":[\"stringProperty\"],\"type\":\"object\",\"properties\":{\"stringProperty\":{\"type\":\"string\"}}}";
-        assertEquals(m.writeValueAsString(p), json);
+        final String json1 = "{\"required\":[\"stringProperty\"],\"type\":\"object\",\"properties\":{\"stringProperty\":{\"type\":\"string\"}}}";
+        String json2 = m.writeValueAsString(p);
+        JSONObject jsonObj1 = new JSONObject(json1);
+        JSONObject jsonObj2 = new JSONObject(json2);
+        JSONAssert.assertEquals(jsonObj1, jsonObj2, true);
     }
 
     @Test(description = "it should deserialize an object property with required set")