selftests/tls: add a test for ULP but no keys

Make sure we test the TLS_BASE/TLS_BASE case both with data
and the tear down/clean up path.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>