selftests: net: remove ioam tests

This patch entirely removes the ioam selftests to prepare for the next
patch in this series, which re-adds the new ioam selftests for better
readability.

Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Link: https://patch.msgid.link/20241002162731.19847-2-justin.iurman@uliege.be


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