Return true if and only if the two given cubics (or genus one models of degree 3) are equivalent as genus one models. In other words, that there exists a linear transformation of the ambient projective space PQ2 which takes one cubic to the other, up to scaling. The algorithm is given in [Fis06].When true, the transformation is also returned as a tuple (the syntax is explained in Section Transformations between Genus One Models, on transformations, below).