We care about the exit code of our server, for example if it's
reporting a memory leak after having otherwise executed correctly.
We don't care about the exit code of the servers we're using for
interoperability testing (openssl s_server, gnutls-serv). We assume
that they're working correctly anyway, and they return 1 (gnutls-serv)
or die by the signal handle the signal (openssl) when killed by a
signal.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>