selftest/bpf: Add tests for sockmap with unix stream type.

Add two tests for unix stream to unix stream redirection
in sockmap tests.

Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210816190327.2739291-4-jiang.wang@bytedance.com

tools/testing/selftests/bpf/prog_tests/sockmap_listen.c

@@ -2020,11 +2020,13 @@ void test_sockmap_listen(void)
 	run_tests(skel, skel->maps.sock_map, AF_INET);
 	run_tests(skel, skel->maps.sock_map, AF_INET6);
 	test_unix_redir(skel, skel->maps.sock_map, SOCK_DGRAM);
+	test_unix_redir(skel, skel->maps.sock_map, SOCK_STREAM);
 
 	skel->bss->test_sockmap = false;
 	run_tests(skel, skel->maps.sock_hash, AF_INET);
 	run_tests(skel, skel->maps.sock_hash, AF_INET6);
 	test_unix_redir(skel, skel->maps.sock_hash, SOCK_DGRAM);
+	test_unix_redir(skel, skel->maps.sock_hash, SOCK_STREAM);
 
 	test_sockmap_listen__destroy(skel);
 }