selftests/net: packetdrill: add ipv4-mapped-ipv6 tests Add ipv4-mapped-ipv6 case to ksft_runner.sh before an upcoming TCP fix in this area. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20260217142924.1853498-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>