selftests/bpf: Cover listener cloning with progs attached to sockmap

Today we test if a child socket is cloned properly from a listening socket
inside a sockmap only when there are no BPF programs attached to the map.

A bug has been reported [1] for the case when sockmap has a verdict program
attached. So cover this case as well to prevent regressions.

[1]: https://lore.kernel.org/r/00000000000073b14905ef2e7401@google.com

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-4-1e0ee7ac2f90@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>