Merge changes from topic "am-c46773e6decc4bb3908c7de93fa63602" into rvc-d1-dev-plus-aosp

* changes:
  Switch back to using stable interfaces for DNS resolver. am: 0d234b06 am: b89de6ce
  [automerger skipped] Freeze IDnsResolver to v5. am: fc3a5314 -s ours am: 9869e048 -s ours
  [automerger skipped] Support DNS64 synthesis using externally-discovered prefixes. am: 346737c0 -s ours am: f7f87cfc -s ours