selftests: netfilter: nft_queue.sh: include file transfer duration in log message

Paolo Abeni says:
 Recently the nipa CI infra went through some tuning, and the mentioned
 self-test now often fails.

The failing test is the sctp+nfqueue one, where the file transfer takes
too long and hits the timeout (1 minute).

Because SCTP nfqueue tests had timeout related issues before (esp. on debug
kernels) print the file transfer duration in the PASS/FAIL message.
This would aallow us to see if there is/was an unexpected slowdown
(CI keeps logs around) or 'creeping slowdown' where things got slower
over time until 'fail point' was reached.

Output of altered lines looks like this:
  PASS: tcp and nfqueue in forward chan (duration: 2s)
  PASS: tcp via loopback (duration: 2s)
  PASS: sctp and nfqueue in forward chain (duration: 42s)
  PASS: sctp and nfqueue in output chain with GSO (duration: 21s)

Reported-by: Paolo Abeni <pabeni@redhat.com>
Closes: https://lore.kernel.org/netdev/584524ef-9fd7-4326-9f1b-693ca62c5692@redhat.com/


Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20250523121700.20011-1-fw@strlen.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>