net: use WARN_ON_ONCE() in sk_stream_kill_queues()

sk_stream_kill_queues() has three checks which have been
useful to detect kernel bugs in the past.

However they are potentially a problem because they
could flood the syslog.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>