Look into multi-process fuzz testing

[lastmjs]

Right now we generally have one process fuzzing per cansiter, with a default call delay of .1 seconds. Setting the call delay to 0 seconds has led to discovery of some pretty good bugs. But this is all just one process...I wonder if testing with multiple cuzz processes, like 5, 10, 20, would lead to discovery of more bugs. Let's consider this for the 1.0, for release candidate we will not require this.