fix test cases like
... prepare the test, create a table or a user
create event ... on schedule every 1 second ... do something ...
... verify that something was done
... cleanup drop event, table or user
here the event scheduler can manage to start the worker for the
second execution of the event, then cleanup happens
and the worker realizes that it cannot change the security context
(as the user is dropped) or cannot insert (as the table is dropped).
followup for 279b0db8c6 (that removed suppression of /Event Schedule/)
* removed universal suppression of everything "Event Schedule" everywhere
* added suppressions in tests as needed
* moved events test to the events suite
* renamed -master.opt -> .opt
* added standard test header
* verified in the test that the error, indeed, was written into the log
* removed useless suppressions
* removed ER_EVENTS_NO_ACL, replaced with ER_OPTION_PREVENTS_STATEMENT
* fixed error message to say exactly what option disabled event scheduler
instead of "this or that or that, you figure it out"
* also fixed old message for SET event_scheduler=
(it was also non-translatable)
* changed to use sql_print_error() when an error is not sent to the user
* removed duplicate hard-coded error message
