Bug: Max AP on next turn when AP regen is 0.

Created by:
- Rogue in arena
- Use adrenaline skill and spend all AP on movement (end turn with 0 AP)
- Hit by opponent with Fossil Strike (causing slow)
- Adrenaline + Slow means -3 AP regen; arena characters have AP regen of 3
- Next turn my Rogue started their turn with 6 AP