Compare the outputs of the two resolvers

[Eh2406]

Currently we only compare the two resolvers by looking at if there is a solution given a particular index. cargoes resolver provides a much richer view of its output. This data can be reconstructed from PubGrub output in a similar manner to the new cycle detection code. It might be useful to compare the results at these more detailed levels.

This only stands a chance of working when the index is limited to the results of a resolution, otherwise the outputs might differ because they are just different resolutions.