Performance improvement: Use cached matrix to speed up knowability test

[eliewolfe]

In DAGs with edges between outcomes nodes we need to check for the right value of the parent when the child node appears in the monomial. This is a sort of "if this operator is present, then these other operators need to be present as well" situation. This is currently implemented as a function within InflationProblem, but can be improved by caching a boolean matrix with the relevant conditions ahead of time. (Note that we don't need to be concerned with orthogonality, as orthogonal operators never appear in our monomials.)