Refactor hitbox algo cache names into an instance property

[pushfoo]

Stacks onto #1792 Rebased onto development, no longer depends on that PR.

Changes

1. Remove name class attribute from hit box algorithm classes
2. Add cache_name per-instance property
3. Update tests

Why

Per discord discussion with einarf, the current cache names are from the old caching system:

I think we can drop the name and just use self.class.name, right?
No need to make it complicated

How to test

./make.py test or pytest tests/unit as usual

Follow-up work

Refactor cache class attribute into a cache_points instance property.

[einarf]

Much better 👍