Retry until all resident apps are healthy. (#6170)
Retry until all resident apps are healthy. (#6170)

Summary:
This change should avoid another possible cause of flakiness.
gsantovena/marathon,gsantovena/marathon,gsantovena/marathon,gsantovena/marathon,mesosphere/marathon,mesosphere/marathon,mesosphere/marathon,mesosphere/marathon,gsantovena/marathon,mesosphere/marathon