pytest-rerunfailures in goth tests

[johny-b]

Things I checked:

• random exceptions like ZeroDivisionError don't cause reruns
• failing await wait_for_event(...) causes reruns

--> this looks like the thing we need.

Unfortunately, a not-very-pretty hack was necessary to make this work. I think that this is acceptable, but I'm curious what others think.

Other options and general research summary are in golemfactory/goth#545