selftests/bpf: Test_progs indicate to shell on non-actions

When a user selects a non-existing test the summary is printed with
indication 0 for all info types, and shell "success" (EXIT_SUCCESS) is
indicated. This can be understood by a human end-user, but for shell
scripting is it useful to indicate a shell failure (EXIT_FAILURE).

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/159363984736.930467.17956007131403952343.stgit@firesoul