Fixes Epic Online Services update hanging when the service needs to be restarted (a helper process is waiting for either service's mutex to be available or QueryServiceStatus to tell that the server is stopped after the service had just exited the process without notifying service control manager).
It seems to me that using a job object is much simpler than the other ways (like waiting on multiple process handles and managing process addition and deletion in the waiters list). I tested that on real up to date Windows 10 machine and there the process has the job object which object has JOB_OBJECT_LIMIT_BREAKAWAY_OK | JOB_OBJECT_LIMIT_SILENT_BREAKAWAY_OK limit flags (and only those). That job has also the other service processes in it but not services.exe itself. However, for some reason on any Testbot machine that is not the case and IsProcessInJob() reports that the process doesn't have a job. But since I do see that job on a real machine I think using job object here is fine.