## About The Pull Request
Adds `EXPERIMENT_515_QDEL_HARD_REFERENCE`, which will queue to the GC
subsystem using hard references rather than `\ref`. This is only
possible in 515 because of the new `refcount` proc. `\ref` is very very
slow and has some nasty knock on effects, so removing its usages where
possible is good.
This is an explicit opt in define because I want to give us the ability
to test 515 on live while only testing 515 itself, not our experimental
changes. We have a few more of these we want to do so I made a separate
file for them. They're auto-defined in unit tests so we see them with
the alternate test runner. In a perfect world we'd test both on and off,
but eh.
Closes https://github.com/tgstation/dev-cycles-initiative/issues/10
0235cfb078