Update `OptimizeSwapBeforeMeasure` to use Rustworkx 0.15 reverse topological order about qiskit

[jakelishman]

Looking more right now, OptimizeSwapBeforeMeasure has several components that are pretty broken, or at least rather unoptimal. DAGCircuit.descendants produces an unordered set (why?), so iterating through that has no particular order, and I don't think it's guaranteed to produce correct results. Similarly, DAGCircuit.op_nodes is not topological, so there's no guarantee that the swaps are visited in the best order, even if reversed.

[mtreinish]

Yeah, my thinking is this pass would be supersceded by ElidePermutations so performance improvements for it shouldn't be critical. Im thinking we'll want to deprecate it in 1.2 for removal in 2.0. But we definitely should try to fix correctness issues for the 1.x branch where we can.

[jakelishman]

I guess the reason it might not be totally supplanted is that this pass might still have worth in a pipeline for a backend that has a native swap - in that case, it might still have value in a post-translation and post-routing optimisation layout, where ElidePermutations would invalidate the coupling constraints. This never invalidates coupling constraints because it's a limited form of swap/permutation elision where it only affects gates that are followed by 1q operations (or other swaps).

That said, we could probably teach ElidePermutations to have a coupling-aware version of itself as well, if we chose.