Handle SetPseudoRandomStamp automatically

[ssiccha]

I haven't thought this through yet completely. My idea is, once we have our own types for methods, see #258, to let CallMethods handle the setting of the RandomStamps, so that we don't have to do it ourselves and thus can't forget about it.

Maybe it would make sense to put the stamps on a stack? Whenever we enter a recog method via CallMethods we put a stamp on the random stamp stack, when we leave the method we pop the stamp off the stack. 🤔