test: expect error for test_lookup_ipv6_hint on FreeBSD

FreeBSD does not support the V4MAPPED flag so expect an error.

This is a partial fix for https://github.com/nodejs/node/issues/2468.
It only fixes it on FreeBSD. Failures on other platforms are due to
other reasons and need to be fixed separately.

PR-URL: https://github.com/nodejs/node/pull/2724


Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Fixes: https://github.com/nodejs/node/issues/2468