selftests/net: bind_bhash: fix memory leak in bind_socket

selftests/net: bind_bhash: fix memory leak in bind_socket

The getaddrinfo() call in bind_socket() dynamically allocates memory
for the result linked list that must be freed with freeaddrinfo().
However, none of the code paths after a successful getaddrinfo() call
free this memory, causing a leak in every invocation of bind_socket().

Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
Link: https://patch.msgid.link/20260601013927.1835-1-yanlonglong@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>