Amend HBASE-12156 TableName cache doesn't used for once of valueOf methods (Andrey Stepachev)

Fix use of diamond operator in TestTableName, we are still using
-source 1.6 for building 0.98

hbase-server/src/test/java/org/apache/hadoop/hbase/util/TestTableName.java

@@ -154,7 +154,7 @@ public class TestTableName extends TestWatcher {
   @Test
   public void testValueOf() {
 
-    Map<String, TableName> inCache = new HashMap<>();
+    Map<String, TableName> inCache = new HashMap<String, TableName>();
     // fill cache
     for (Names name : names) {
       inCache.put(name.nn, TableName.valueOf(name.ns, name.tn));