This is a backport of CASSANDRA-11038.
Before this, a restarted node will be reported as new node with NEW_NODE
cql notification.
To fix, only send NEW_NODE notification when the node was not part of
the cluster
Fixes: #3979
Tests: pushed_notifications_test.py:TestPushedNotifications.restart_node_test
Message-Id: <453d750b98b5af510c4637db25b629f07dd90140.1544583244.git.asias@scylladb.com>
(cherry picked from commit 71c1681f6c)