selftest: bpf: Add test for bpf_tcp_sock() and RAW socket.

selftest: bpf: Add test for bpf_tcp_sock() and RAW socket.

Let's extend sockopt_sk.c to cover bpf_tcp_sock() for the
wrong socket type.

Before:
  # ./test_progs -t sockopt_sk
  [  151.948613] ==================================================================
  [  151.951376] BUG: KASAN: slab-out-of-bounds in sol_tcp_sockopt+0xc7/0x8e0
  [  151.954159] Read of size 8 at addr ffff88801083d760 by task test_progs/1259
  ...
  run_test:FAIL:getsetsockopt unexpected error: -1 (errno 0)
  #427     sockopt_sk:FAIL

After:
  #427     sockopt_sk:OK

While at it, missing free() is fixed up.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260504210610.180150-3-kuniyu@google.com