[BUG] excessive reservations in case of "split" platforms

[Mariculous]

What happened?
TCB will create excesive reservations if a platform is split and a train stops at the first platform.

How to reproduce?
1. open the attached save, enable the block reservation tool.
2. Spectate the two trains.
- The first train will properly drive to land stop 2
- The second train will properly follow to land stop 1
- When the second train is about to depart at land stop 2, it will create a reservation up to the platform around the corner.
- Note: it is not meant to use that platform at all.
- Deadlock!
3. Launch the trains in the upper depot
4. Spectate the trains, the same as obove will happen.

Note that such a layout might look weird in the first place, but appears fairly frequently in tram networks, where a crossing bus line will use the here unused platform.

[jamespetts]

I note that I had missed this report from some time ago and then it had got to page 3 of the development forum out of sight - I will note this to look into it when I have a moment.