Actually resolve all IPs for Private DNS hostname

Previously, we reused the OneAddressPerFamilyNetwork which does
what it says on the tin.  For the resolution that will be used
to program netd this is not what we really want.

Test: as follows
    - built
    - flashed
    - booted
    - runtest frameworks-net passes
    - manual testing of Private DNS passes
Bug: 64133961
Merged-In: I1e5de255c4ee11f46dc8a1e3f5eaca2f2be1c792
Merged-In: Ia52675649a17f25f1baff9393f8a50b586893a56
Change-Id: Ieccc4d208b314b81061dc78d83848f97acefe04b
(cherry picked from commit 71d90c43)