=rem #3566 Fix failing RemoteNodeRestartDeathWatchSpec

* Subject actor in freshSystem was not started when the "shutdown"
  message was sent. Solved by retry.
(cherry picked from commit 52f7d2d47873e10e6d6d85292949f8a4bcb2a13a)
Merge pull request #1708 from akka/wip-3566-RemoteNodeRestartDeathWatchSpec-2.2-patriknw

=rem #3566 Fix failing RemoteNodeRestartDeathWatchSpec (backport)