Because normals are calcualted lazily for all cases "depends_on_normals"
except for BMesh original normals, this is mostly unnecessary. It's actually
probably not necessary at all, because in practice there is always a separate
positions array stored in `EditMeshData` during mesh edit mode modifier
evaluation, bringing us back to the lazy calculation. But anyway, removing
the usage for topology-changing modifiers and modifiers which don't
accept BMesh as input anyway simplifies things.
Pull Request: https://projects.blender.org/blender/blender/pulls/120274
b195014e05