- disentangled test_icmp_client and test_icmp_server's logics
- integrated more error-reporting changes for nat_test.c

git-svn-id: https://gnunet.org/svn/gnunet@33525 140774ce-b5e7-0310-ab8b-a85725594a96
-fix #3428

git-svn-id: https://gnunet.org/svn/gnunet@33526 140774ce-b5e7-0310-ab8b-a85725594a96
-rename

git-svn-id: https://gnunet.org/svn/gnunet@33527 140774ce-b5e7-0310-ab8b-a85725594a96