selftest: tcp: Add v4-mapped-v6 cases in bind_wildcard.c.

We add these 8 test cases in bind_wildcard.c to check bind() conflicts.

  1st bind()          2nd bind()
  ---------           ---------
  0.0.0.0             ::FFFF:0.0.0.0
  ::FFFF:0.0.0.0      0.0.0.0
  0.0.0.0             ::FFFF:127.0.0.1
  ::FFFF:127.0.0.1    0.0.0.0
  127.0.0.1           ::FFFF:0.0.0.0
  ::FFFF:0.0.0.0      127.0.0.1
  127.0.0.1           ::FFFF:127.0.0.1
  ::FFFF:127.0.0.1    127.0.0.1

All test passed without bhash2 and with bhash2 and this series.

 Before bhash2:
  $ uname -r
  6.0.0-rc1-00393-g0bf73255d3a3
  $ ./bind_wildcard
  ...
  # PASSED: 16 / 16 tests passed.

 Just after bhash2:
  $ uname -r
  6.0.0-rc1-00394-g28044fc1d495
  $ ./bind_wildcard
  ...
  ok 15 bind_wildcard.v4_local_v6_v4mapped_local.v4_v6
  not ok 16 bind_wildcard.v4_local_v6_v4mapped_local.v6_v4
  # FAILED: 15 / 16 tests passed.

 On net.git:
  $ ./bind_wildcard
  ...
  not ok 14 bind_wildcard.v4_local_v6_v4mapped_any.v6_v4
  not ok 16 bind_wildcard.v4_local_v6_v4mapped_local.v6_v4
  # FAILED: 13 / 16 tests passed.

 With this series:
  $ ./bind_wildcard
  ...
  # PASSED: 16 / 16 tests passed.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>