Interpreter that fuzzes the topo-sort of unordered operations

Our serial interpreters execute in program order, so even when some operations are unordered wrt each other, in practice some (potentially arbitrary) order is chosen. It can be difficult to check that a token graph is constructed correctly. One possible solution to this is to have an interpreter that randomly shuffles the program order (still respecting the token graph), Perhaps shuffling once at interpreter construction or after every tick.