reuseport, bpf: add test case for bpf_get_numa_node_id

The test case is very similar to reuseport_bpf_cpu, only that here
we select socket members based on current numa node id.

  # numactl -H
  available: 2 nodes (0-1)
  node 0 cpus: 0 1 2 3 4 5 12 13 14 15 16 17
  node 0 size: 128867 MB
  node 0 free: 120080 MB
  node 1 cpus: 6 7 8 9 10 11 18 19 20 21 22 23
  node 1 size: 96765 MB
  node 1 free: 87504 MB
  node distances:
  node   0   1
    0:  10  20
    1:  20  10

  # ./reuseport_bpf_numa
  ---- IPv4 UDP ----
  send node 0, receive socket 0
  send node 1, receive socket 1
  send node 1, receive socket 1
  send node 0, receive socket 0
  ---- IPv6 UDP ----
  send node 0, receive socket 0
  send node 1, receive socket 1
  send node 1, receive socket 1
  send node 0, receive socket 0
  ---- IPv4 TCP ----
  send node 0, receive socket 0
  send node 1, receive socket 1
  send node 1, receive socket 1
  send node 0, receive socket 0
  ---- IPv6 TCP ----
  send node 0, receive socket 0
  send node 1, receive socket 1
  send node 1, receive socket 1
  send node 0, receive socket 0
  SUCCESS

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>