Blender Git Loki

Geometry Nodes: Distribute points once per instance reference

With this commit, the distribute points on faces node runs only
once for every unique mesh in its input. That means if there are
100 instances of the same mesh, it will only run once.

This basically reverts rB84a4f2ae68d408301. The optimization there
didn't end up being worth it in the end, since it complicates code
quite a lot. It's also incompatible with this method of dealing with
instances, and it breaks field evaluation for instances, where we would
have to make sure to handle each instance transform properly otherwise,
evaluating the field separately for every instance.

Differential Revision: https://developer.blender.org/D12630