Blender Git Loki

Fix T80967: Alembic, crash when the imported sim from Houdini starts

Compare mesh loop count with number of loop normals before reading the
loop normals.

Houdini doesn't always write the correct loop normals to Alembic. When a
mesh is animated and then replaced by a fluid simulation, Houdini will
still write the original mesh's loop normals, but the mesh
verts/loops/polys are from the simulation. In such cases the normals
cannot be mapped to the mesh, so it's better to ignore them.