Also fix a couple other places where normals layers weren't properly
tagged dirty or reallocated when the mesh changes.
Caused by cfa53e0fbe. When the size of a mesh changes,
the normal layers need to be reallocated. There were a couple of places
that cleared other runtime data with `BKE_mesh_runtime_clear_geometry`
but didn't deal with normals properly. Clearing the runtime "geometry"
is different from clearing the normals, because sometimes the size of
the normal layers doesn't have to change, in which case simply tagging
them dirty is fine.
7b37d980b9