cJSON_Compare: Fix comparison of arrays

It did consider two arrays equal if one is a prefix of the other one,
which is incorrect.

See #180

cJSON.c

@@ -2594,6 +2594,11 @@ CJSON_PUBLIC(cJSON_bool) cJSON_Compare(const cJSON * const a, const cJSON * cons
                 b_element = b_element->next;
             }
 
+            /* one of the arrays is longer than the other */
+            if (a_element != b_element) {
+                return false;
+            }
+
             return true;
         }