LTN 2.7.0 bug: scheduler uses item count instead of priority

[half a cat]

When LTN chooses a provider station, it ignores priority and chooses the provider with the largest item count. I believe that LTN should choose the highest-priority provider that can fulfill a request.

I found this bug because my factory had a station for recycling byproducts that was never being used, causing the factory to back up. Although the byproduct station had a higher priority than the new product station, trains would only go to the byproduct station if I made the new product station appear to be empty (by disconnecting circuit wires).

The attached save file demonstrates the behavior. In the save file, there is a high priority provider and a low priority provider. These two stations have the same LTN signals except for priority. The train always goes to the low priority provider. By adjusting the amount of fluid, you can make it go to the high priority provider instead, showing that LTN is scheduling based on the item count and not based on the priority.