Merge branch 'selftests-net-improve-error-handling-in-passive-tfo-test'

Yohei Kojima says:

====================
selftests: net: improve error handling in passive TFO test

This series improves error handling in the passive TFO test by (1)
fixing a broken behavior when the child processes failed (or timed out),
and (2) adding more error handlng code in the test program.

The first patch fixes the behavior that the test didn't report failure
even if the server or the client process exited with non-zero status.
The second patch adds error handling code in the test program to improve
reliability of the test.
====================

Link: https://patch.msgid.link/cover.1768312014.git.yk@y-koj.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>