[3.1.1] Backport TestReconnectReplicator fix

Flaking test fix for TestReconnectReplicator where asserting on replicator status enter reconnecting state and then finally running state again causes flakes.

Fix now asserts on connection stat incrementing to indicate that the replicator disconnects and reconnects and just asserts on the replicator state entering a running state again.

fix was here -> https://github.com/couchbase/sync_gateway/pull/6296