`show create table` should fail when the user only has `create temporary table` privilege

[djshow832]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql -h127.1 -uroot -P4000

mysql> create database tmpdb;
Query OK, 0 rows affected (0.01 sec)

mysql> create table tmpdb.t(id int);
Query OK, 0 rows affected (0.01 sec)

mysql> drop user test_user;
Query OK, 0 rows affected (0.01 sec)

mysql> create user test_user;
Query OK, 0 rows affected (0.01 sec)

mysql> grant create temporary tables on tmpdb.* to test_user;
Query OK, 0 rows affected (0.00 sec)

mysql -h127.1 -utest_user -P4000

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| INFORMATION_SCHEMA |
| tmpdb              |
+--------------------+
2 rows in set (0.00 sec)

mysql> use tmpdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+-----------------+
| Tables_in_tmpdb |
+-----------------+
| t               |
+-----------------+
1 row in set (0.00 sec)

mysql> show create table t;
+-------+------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                               |
+-------+------------------------------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

2. What did you expect to see? (Required)

mysql -h127.1 -utest_user -Ac

mysql> use tmpdb;
Database changed
mysql> show tables;
Empty set (0.01 sec)

mysql> show create table t;
ERROR 1142 (42000): SHOW command denied to user 'test_user'@'localhost' for table 't'

3. What did you see instead (Required)

mysql -h127.1 -utest_user -P4000

mysql> use tmpdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+-----------------+
| Tables_in_tmpdb |
+-----------------+
| t               |
+-----------------+
1 row in set (0.00 sec)

mysql> show create table t;
+-------+------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                               |
+-------+------------------------------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

4. What is your TiDB version? (Required)

master