Attempt to make the test more robust against cases where the sender
does not notice the connection has dropped until after it tries sending
a well-formed message.


git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10637 ddefafc4-47db-0310-ae44-fa13212b10f2
release: Update for 1.9.0~beta6

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10638 ddefafc4-47db-0310-ae44-fa13212b10f2
See if we can force the sender to notice the connection has dropped by sending a stun ping.


git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10639 ddefafc4-47db-0310-ae44-fa13212b10f2