clock: tag test files with current version

exercises/clock/src/test/java/ClockAddTest.java

 
 import static org.junit.Assert.assertEquals;
 
+/*
+ * version: 1.0.1
+ */
 public class ClockAddTest {
 
     @Ignore("Remove to run test")

exercises/clock/src/test/java/ClockCreationTest.java

 
 import static org.junit.Assert.assertEquals;
 
+/*
+ * version: 1.0.1
+ */
 public class ClockCreationTest {
 
     @Test

exercises/clock/src/test/java/ClockEqualTest.java

 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+/*
+ * version: 1.0.1
+ */
 public class ClockEqualTest {
 
     @Ignore("Remove to run test")