Mtest: remove legacy --at option. This implies removing the "Killed" outcome of a test.
Mtest: remove legacy --at option.
This implies removing the "Killed" outcome of a test.

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb