core: when loading an infra, identify if the geo coordinates can reliably be used for heuristics

[eckter]

All infras have geo coordinates and we want to use them for heuristics, but sometimes the values are just arbitrary and don't reflect actual distances. This is the case in generated infras.

We should have a new field / getter in the TrackInfra class that indicates whether the coordinates match the track lengths. This doesn't need to be a new parameter, we can check when loading an infra by comparing some track lengths with their coordinates.

Needed for #2817.