Remove uneeded TODOs at test_gc.py (#2451)
Remove uneeded TODOs at test_gc.py (#2451)

* Remove uneeded TODOs

* fix fixtures

* Remove TODO and add comments about overwriting

* use local_worker.close()

OpenMined/PySyft,OpenMined/PySyft,OpenMined/PySyft,OpenMined/PySyft