To check that, for all parameter valuations in a region,
(1) some threshold property holds or (2) that a given
scheduler is optimal, a set of constraints is checked.
Currently, only heuristic checking is implemented, i.e., determining
via sampling if the constraints hold. This can produce false positives
in the region computations, i.e., a region is not sufficiently split.
We add a warning if the region computation relied on the heuristic
constraint check and thus can be imprecise.