Add a check in a test that started to fail on Travis
Add a check in a test that started to fail on Travis

The failure is due to some slowness on Travis. We are checking
that some messages have expired (but not all), but between a sleep
and the time we check, much more time than expected has elapsed.
If that is the case, skip the check.

Signed-off-by: Ivan Kozlovic <a15f8b81a160b4eebe5c84e9e3b65c87b9b2f18e@synadia.com>

nats-io/nats-streaming-server,nats-io/nats-streaming-server