This fixes issues with a lot of moves, including but not limited to Acid, Beat Up, Bone Rush, Crunch, Dig, Extreme Speed, Fake Out, Future Sight, High Jump Kick, Hypnosis and Petal Dance.
In Gen 2,moves with negative priority work with negative speed.
It's the slower phazing move that will work first.
To achieve this, gen 2 runs its own compare priority and the functions
which use this one are edited so they use the custom compare priority.