Backport Bug #43913  rpl_cross_version can't pass on conflicts complainig clash with --slave-load-tm

The 'rpl_cross_version' fails on mysql-next-mr-bugfixing as following:
mysqltest: In included file "./include/setup_fake_relay_log.inc": At line 80: query
'select './$_fake_filename-fake.000001\n' into dumpfile '$_fake_relay_index'' failed:
1290: The MySQL server is running with the --secure-file-priv option so it cannot execute
this statement.

To fix the problem by removeing the --secure-file-priv option
for adapting the update of the 'setup_fake_relay_log.inc'.