Remove stale operating_system.py test per discussion in #1631
Remove stale operating_system.py test per discussion in #1631

- Test has not been registered in `__init__.py` for a while and needs a
  refresh.

mfherbst/spack,krafczyk/spack,skosukhin/spack,TheTimmy/spack,iulian787/spack,tmerrick1/spack,LLNL/spack,EmreAtes/spack,skosukhin/spack,iulian787/spack,lgarren/spack,TheTimmy/spack,EmreAtes/spack,LLNL/spack,matthiasdiener/spack,TheTimmy/spack,lgarren/spack,mfherbst/spack,skosukhin/spack,LLNL/spack,iulian787/spack,TheTimmy/spack,mfherbst/spack,krafczyk/spack,tmerrick1/spack,matthiasdiener/spack,mfherbst/spack,lgarren/spack,EmreAtes/spack,matthiasdiener/spack,skosukhin/spack,tmerrick1/spack,lgarren/spack,tmerrick1/spack,matthiasdiener/spack,EmreAtes/spack,lgarren/spack,krafczyk/spack,krafczyk/spack,LLNL/spack,EmreAtes/spack,TheTimmy/spack,matthiasdiener/spack,mfherbst/spack,skosukhin/spack,iulian787/spack,iulian787/spack,tmerrick1/spack,LLNL/spack,krafczyk/spack