Thread might be alive, but hung on data recv/send. With this check
the test is interrupted after 1s of inactivity. It doesn't check for
new data on the sender thread as with some settings (big send buffer
and small recv buffers) the queue might be filled and this thread
has to wait for new data. This is expected behaviour.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>