selftests: netfilter: add nfqueue TCP_NEW_SYN_RECV socket race test

causes:
BUG: KASAN: slab-out-of-bounds in sk_free+0x25/0x80
Write of size 4 at addr ffff888106df0284 by task nf-queue/1459
sk_free+0x25/0x80
nf_queue_entry_release_refs+0x143/0x1a0
nf_reinject+0x233/0x770

... without 'netfilter: nf_queue: don't assume sk is full socket'.

Signed-off-by: Florian Westphal <fw@strlen.de>