- `bmesh_radial_faceloop_find_first` & `bmesh_disk_faceedge_find_first`
can be replaced with a single call to a new function:
`bmesh_disk_faceloop_find_first`
- `bmesh_disk_faceedge_find_first` called `bmesh_radial_facevert_check`
which isn't needed, since either the current or next loop in the
cycle is attached to the edge we're looking for.