Bug: user privilege check should be compatible with mysql 5.7

[StrikeW]

It seems to be because of the mysql version.

mysql> SELECT VERSION();
+------------+
| VERSION()  |
+------------+
| 5.7.36-log |
+------------+

I also tested mysql 5.7 with a new created user bob and grant all to the bob.

mysql> CREATE USER 'bob'@'%' IDENTIFIED BY 'password';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT ALL PRIVILEGES ON *.* TO 'bob'@'%';
Query OK, 0 rows affected (0.01 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.01 sec)

mysql> SHOW GRANTS FOR 'bob';
+------------------------------------------+
| Grants for bob@%                         |
+------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'bob'@'%' |
+------------------------------------------+
1 row in set (0.00 sec)

mysql -h 10.8.16.9 -P 3306 -u bob -ppassword

mysql> show grants;
+------------------------------------------+
| Grants for bob@%                         |
+------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'bob'@'%' |
+------------------------------------------+

mysql> SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000044 |     4818 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

So maybe consider compatibility with mysql 5.7?

Originally posted by @jho-yf in #12479 (comment)

[StrikeW]

The GRANT ALL in MySQL 5.7 is ambiguous, we should suggest user to grant required privileges explicitly via the following command:

GRANT SELECT, RELOAD, SHOW DATABASES, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'user'@'%';