Draft: Remove runaway script termination.

This topic simply removes runaway script termination entirely.

This is something that has come up a few times but not much has been done about it. I created this topic primarily to push discussion of the issue forward and hopefully reach some agreement on it.

Removing the check entirely is a solution that was brought up on the dev channel of the ZDoom Discord server and was the most accepted fix, but making it a compat flag has also been brought up before (and a patch was made by drinkybird some time ago, though nothing came of it). Finally, adding a BUSY script flag has been suggested as well. This would require modifications to ACC (and of course the other compilers) however, and AFAICT wouldn't get into GZDoom.

I believe just removing the check minimizes the delta with GZDoom and deals with the issue very easily. But there's valid concerns that it may cause some old mods that depend on runaway script termination to stop working, and it does remove a safety feature (one that admittedly isn't present for anything else in ZDoom, though).