Qubit pairs containing both symmetric and asymmetric gates

[stavros11]

Something else I noticed about the pairs and symmetry using the dummy, is that for (2, 3) we register both CZ and CNOT but because the CNOT is not symmetric, it correctly does not register (3, 2). In principle, we could still register just the CZ, which is symmetric, for (3, 2). However, this case is a bit tricky and I don't even think it is handled in 0.1, so I would certainly not do anything about it here.

Originally posted by @stavros11 in #971 (comment)