Show create table should display pre_split_regions if possible

[tangenta]

Enhancement

mysql> CREATE TABLE `t` (   `a` bigint(20) NOT NULL /*T![auto_rand] AUTO_RANDOM(2) */ ,   `b` int(11) DEFAULT NULL,   PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */ ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin /*T! PRE_SPLIT_REGIONS=2 */;
Query OK, 0 rows affected, 1 warning (0.13 sec)

mysql> show create table t;
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                                                                                                   |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `a` bigint(20) NOT NULL /*T![auto_rand] AUTO_RANDOM(2) */,
  `b` int(11) DEFAULT NULL,
  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

PRE_SPLIT_REGIONS disappeared in result.