Removed unneeded ExpectedException

exercises/twelve-days/src/test/java/TwelveDaysTest.java

 import org.junit.Ignore;
-import org.junit.Rule;
 import org.junit.Test;
-import org.junit.rules.ExpectedException;
 
 import static org.junit.Assert.assertEquals;
 
 public class TwelveDaysTest {
-    @Rule
-    public ExpectedException expectedException = ExpectedException.none();
 
     @Test
     public void testVerseOne() {