Compare Cholesky and BunchKaufman by properties

[jishnub]

The fields of a Factorization are more of an implementation detail, and a factorization is usually uniquely identified by its properties. Therefore, it makes sense to check if two Factorizaitons are equal by comparing their properties. I've implemented this for Cholesky and BunchKaufman, as these are the ones where the properties are wrappers around the field arrays, and therefore their values differ.

In particular, this would make such comparisons work even if the parents of the AbstractTriangular factors have uninitialized elements corresponding to the structural zeros of the triangular wrappers. Currently, this throws an error as it tries to compare the parents (which are the fields of the Factorization objects), but this is unnecessary. What really matters is that the triangular factors are equal.

This will make the comparisons slower in general, as new arrays may need to be allocated or computed. However, comparing two Factorization objects is probably unlikely to feature in a performance-sensitive path, and is perhaps more likely to feature in tests.