Removed deprecated security manager from SortThreePairs

sort_three_pairs/src/test/java/edu/unl/cse/soft160/sort_three_pairs/SortThreePairsTest.java

@@ -55,16 +55,6 @@ public class SortThreePairsTest {
         }
     }
 
-    @Before
-    public void setUp() throws SecurityException {
-        System.setSecurityManager(new TestingSecurityManager());
-    }
-
-    @After
-    public void tearDown() throws SecurityException {
-        System.setSecurityManager(null);
-    }
-
     protected static String runMainForError(int expectedStatus, String... arguments) {
         InputStream in = System.in;
         PrintStream err = System.err;