The UnregisterGroup test leaves the unregistered group's process executing
after the test completes. When RMID is shutdown, it does not destroy the
group's process since the group was unregistered and RMID no longer has
knowledge of the group (or the fact that it spawned the child process in
the first place). It is actually unclear what RMID should do in this
case. When RMID is shutdown, is it RMID's responsibility to clean up (i.e.,
destroy) child groups that have been unregistered? Or should the group
clean itself up?

For now, the test can be cleaned up so that it does not leave around a
dangling process. Each object in the group can be deactivated so that
the group can exit on its own.