Added explicit internal roofs to Karting

[PatrikLundell]

Summary

None

Purpose of change

Add explicit internal roofs to karting rather than relying on add_roofs magic.

Describe the solution

Modify the JSON upper floor definition. Concrete floors was used to match building, rather than flat roof which add_roofs magic would provide (with walls doors, etc. giving other results).

Describe alternatives you've considered

• Different floor material? I think concrete matches the building best.
• Cover the racetrack office? It was designed with no roof...
• Add windows overlooking the pool area.

Testing

Debug spawn building, teleport to it, inspect it.

Additional context

The code used is hacked to disable add_roofs in order to find missing roof definitions. This means the track office walls and the internal wall/door shown without roofs in the image will be covered by whatever roof those tiles place above them in the actual game, until add_roofs is disabled.