lo: add a way to run an Online unit test multiple times
lo: add a way to run an Online unit test multiple times

unit-crash is unstable with sanitizers, so I want to run it like 10
times to see if the failure is real or just timing.

vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam,vmiklos/vmexam