let's always disconnect a user connection before dropping the said user.
MariaDB is traditionally very tolerant to active connections
of the dropped user, which isn't the case for most other databases.
Let's avoid unintentionally spreading incompatible behavior
and disconnect before drop.
Except in cases when the test specifically tests such a behavior.
- Added missing information about database of corresponding table for various types of commands
- Update some typos
- Reviewed by: <vicentiu@mariadb.org>
