OBJ Export: Remove edge recalculation

The removed function call removes all attributes from mesh edges
and rebuilds the mesh edge topology. This isn't necessary because
meshes always have edges in the first place.

Exporting a 4 million face grid, this saved 1.5 seconds out of 4
seconds total for the whole export.

Tests files have to be updated, since the edge calculation could
potentially change the order of elements. This is also a fix, since
previously the exporter would delete all attributes on the evaluated
mesh edges.

Differential Revision: https://developer.blender.org/D16391

source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc

@@ -183,7 +183,6 @@ void OBJMesh::ensure_mesh_normals() const
 
 void OBJMesh::ensure_mesh_edges() const
 {
-  BKE_mesh_calc_edges(export_mesh_eval_, true, false);
   BKE_mesh_calc_edges_loose(export_mesh_eval_);
 }