Disable loop checks during unit tests

[noelle-lavenza]

About the pull request

Hopefully fixes a bunch of flaky create-and-destroy failures. Tentatively I'm saying this should close all the flaky create-and-destroy issues open, because a lot of them are too old to still have the relevant logs.

Also fixes an issue with roundstart lazyloading atoms, where they could end up qdeleted and then be lateinitialized in an invalid state. We now skip qdeleted atoms in the roundstart_loaders list.

The warning for enabling loop_checks is now ignored during unit testing and COMPILE_ALL_MAPS. However, it's still checked in the linting step, which ensures it won't accidentally get enabled on the live server.

Explain why it's good for the game

Fixes flaky create-and-destroy failures. What I think was happening is that the background loop checks caused stuff to start running in parallel; a background proc will yield at loop points, meaning stuff will run before/after it should.

Also fixes an issue that could cause certain atoms to runtime in Destroy() and fail to clean up all the references they ought to.

Testing Photographs and Procedure

This will only really be testable by checking CI.

Changelog

🆑 MoondancerPony
code: unit tests should have fewer flaky failures now
/:cl: