Since my changes, rpl_log.test, whose result file depends on file_id, became
non-repeatable, i.e. file_id on slave in SHOW BINLOG EVENTS
changed depending on the order of tests (sometimes 1, sometimes 5).
Which is logical: as now the slave does not copy Create_file and Exec_load from
the relay log (i.e from the master's binlog) to the slave's binlog, but
instead lets mysql_load() do the logging, the file_id is now the one whic
was used on the slave. Before it was the one which was used on the master,
and by chance the master was always restarted for this test because there's
a -master.opt file, so file_id on the master is always 1. But now file_id is
from the slave so we need to restart the slave. That's why I add an (empty)
-slave.opt file. I could have used 'server_stop/start slave', but this
would have required the manager, so most of the time mysql-test-run silently
skip the test which makes it useless. And I want this test to be run !