Blender Git Loki

BMesh: remove BMEditMesh.ob pointer

Remove this pointer since it's linking Mesh data back to the object,
where a single edit-mesh may have multiple object users,
causing incorrect assumptions in the code.

Resolves dangling pointer part of the T72667 crash,
although there are other issues which still need to be fixed.

In EDBM_op_finish and EDBM_update_generic,
full Main lookups have been added which should be replaced with mesh
argument or the update tagging moved elsewhere.