MEDIUM: checks: avoid waking the application up for pure TCP checks

MEDIUM: checks: avoid waking the application up for pure TCP checks

Pure TCP checks only use the SYN/ACK in return to a SYN. By forcing
the system to use delayed ACKs, it is possible to send an RST instead
of the ACK and thus ensure that the application will never be needlessly
woken up. This avoids error logs or counters on checked components since
the application is never made aware of this connection which dies in the
network stack.