Opening & closing recording leaks a memory every time

[Wumpf]

Haven't dived in yet how much exactly leaks, but when I open and close arkitscenes on 0.21 repeatedly the memory usage goes up.
The first time I expect some memory to linger because some of the caches aren't associated with recordings (for instance the cpu/gpu belts) but most should be by now. Also, this behavior continuous after many more attempts.