change the internal layout of the pfmeasurements result for better memory locality

[Krastanov]

The results of pfmeasurements and more generally the way we store measurement results in the Pauli frame object is not local. We should not change the order of the indices in the user-facing interface because they neatly map to the indices of a tableau, but we should change the ordering internally (e.g. by using the transpose view) to make the access faster.