Make sure all instantiations are done and everything is properly linked,
scheduled and optimized. You should normally not need to call this (it
should be called automatically), but we provide it anyway.
— Procedure: next [num-cycles]
Simulate for num-cycles. If omitted, num-cycles defaults to 1.
— Procedure: permute top-level-instance ...
Permute the inputs of top-level-instance ..., allowing one
cycle per permutation. This is useful for characterizing combinational
logic.