Investigate severe performance degradation

[wallabra]

Over the course of but mere minutes, a match that has even just one ZetaBot will eventually become unplayable and unbearably slow, at least in latest GZDoom. Of course, the more bots, the faster this happens. However, it is a gradual process -- merely spawning the bots in will not cause this sharp decay. Targeting enemies, and particularly hunting them, seems to accelerate this process. It cannot be undone, not even by resetting all the ZetaBot states by letting them respawn after a kill command. This may or may not affect maps void of nodes, but this issue might be more reproducible in levels with a fully setup path network.

Hunting generally uses a pathfinder on the path network to path to the last seen position, although the exact relevancy of that is currently unknown.

[wallabra]

One of the changes I made in v0.10.0 was to implement a thinkTimer in ZTBotController that would ensure that most of A_ZetaTick would only be executed every 3 tics. It does seem to slow down the issue, but did not fix at all, which suggests that there is no limit to how bad it can get.

[wallabra]

Data structures in ZetaCode/Standard.zsc have been rewriten, and performance has improved significantly, but it still decreases sharply over time. Further investigation is due.