Y-simplify each individual goal in a GoalComposite?

Not sure if this is a good idea, due to the mismatched heuristics (from the Y level being present vs not present)...
Perhaps it could be an "all or nothing thing"? If they're all in loaded chunks, don't y-simplify (obviously), and if they're all out of loaded chunks, y-simplify? (right now it never y-simplifies a goal composite). And then if it's a mix, err on the side of not simplifying? I think that's best.

Moved from https://github.com/cabaletta/baritone/commit/f0c3e59a6fc085e0c6fd734e2f4c162895f26be6

The issue names GoalComposite and y-simplification but provides no file, test, or entry point. Start by locating GoalComposite and the existing y-simplification logic, then resolve the proposed all-or-nothing behavior for loaded, unloaded, and mixed goals; done means the chosen rule is implemented and verified.

Written by the indexing model from the issue text.