nondeterministic test results in spider/bugfix.self_reference_multi

Happens quite often:

https://buildbot.mariadb.net/ci/reports/cross_reference#branch=&revision=&platform=&fail_name=spider/bugfix.self_reference_multi&fail_variant=&fail_info_full=&typ=&info=&dt=&limit=100&fail_info_short=

Could probably be quickly fixed by a regex replace of the query result - doesn't really matter on which node of the loop the loop is reported - all these outcomes are correct.

It would be good to find out why this happens too.