Expand fuzzing to SliceVec #96

Right now we have a pretty good fuzzing setup for TinyVec and ArrayVec types that has found a number of bugs. We should extend this to cover SliceVec and ArraySet types as well.

SliceVec fuzzing harness is going to be mostly identical to that of ArrayVec. As for ArraySet, rutenspitz ships with plenty of examples for testing map types: https://github.com/jakubadamw/rutenspitz/tree/master/examples/src