Fix recent build failure:

Recent merge of 4da60e3 (#5510) was
calling a method that had been removed (SystemTables.containsTableName).
It seems the method was probably removed on accident, so added it back.

Author: kevinrr888

core/src/main/java/org/apache/accumulo/core/metadata/SystemTables.java

@@ -61,6 +61,8 @@ private SystemTables(String simpleName, String id) {
 
   private static final Set<TableId> ALL_IDS =
       Arrays.stream(values()).map(SystemTables::tableId).collect(Collectors.toUnmodifiableSet());
+  private static final Set<String> ALL_NAMES =
+      Arrays.stream(values()).map(SystemTables::tableName).collect(Collectors.toUnmodifiableSet());
 
   private static final Map<String,String> TABLE_ID_TO_SIMPLE_NAME =
       Arrays.stream(values()).collect(Collectors.toUnmodifiableMap(
@@ -82,6 +84,10 @@ public static boolean containsTableId(TableId tableId) {
     return ALL_IDS.contains(tableId);
   }
 
+  public static boolean containsTableName(String tableName) {
+    return ALL_NAMES.contains(tableName);
+  }
+
   public static Map<String,String> tableIdToSimpleNameMap() {
     return TABLE_ID_TO_SIMPLE_NAME;
   }