Reuse existing triangles in Triangles background

[EVAST9919]

As per comment.
Unfortunately I'm not able to reproduce such a big impact of triangles using linked pr (or at all really). In my case usage was low in the first place and went from 0.9% to 0.6% with this pr, so outside benchmarking would be great

Improvement list:

• No more sorted list. Basic list is being used which is sorted once after all the triangles added.
• Out-of-bounds triangles are reused rather than removed and re-added.
• On Reset if AimCount stays the same, all triangles are reused instead of being cleared and re-added.

[peppy]

Unfortunately I'm not able to reproduce such a big impact of triangles using linked pr (or at all really).

I think it is unfairly(?) high in the headless testing because 100% of the time is being spent on cpu bound operations. Also I was filtering out sleep. So you have 3 minutes of gameplay compressed to 1.4 seconds of all the most expensive stuff going on at once.

Which is to say, I think this will make a difference, even if it tests small in the grand scheme 👍