Geometry debugging mode (cell overlap checks) don't work for DAGMC geometries

[paulromano]

Bug Description

If you try to run OpenMC on a DAGMC geometry and turn geometry debugging on, it will always crash out reporting overlapping cells even when there are none. It appears that this happens when a particle crosses a surface and based on the check that is performed, it thinks that the particle is in both cells (probably due to numerical precision?).

Steps to Reproduce

Take any DAGMC model and run it with openmc -g from the command line or openmc.run(geometry_debug=True) from the Python API.