selftests: net: add new ioam tests

This patch re-adds the (updated) ioam selftests with support for the
tunsrc feature.

Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Link: https://patch.msgid.link/20241002162731.19847-3-justin.iurman@uliege.be


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