Merge branch 'selftests-updates-to-fcnal-test-for-autoamted-environment'

David Ahern says:

====================
selftests: Updates to fcnal-test for autoamted environment

The first patch updates the PATH for fcnal-test.sh to find the nettest
binary when invoked at the top-level directory via
   make -C tools/testing/selftests TARGETS=net run_tests

Second patch fixes a bug setting the ping_group; it has a compound value
and that value is not traversing the various helper functions in tact.
Fix by creating a helper specific to setting it.

Third patch adds more output when a test fails - e.g., to catch a change
in the return code of some test.

With these 3 patches, the entire suite completes successfully when
run on Ubuntu 23.10 with 6.5 kernel - 914 tests pass, 0 fail.
====================

Link: https://lore.kernel.org/r/20240124214117.24687-1-dsahern@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>