Initialize callbacks in fuzzer am: 857ece4f am: 42b71bab am: e82f323e am: e4d3cde5 am: 767e8774

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/2469762



Change-Id: I3c0302f07446596116de2f695e4315e8b68e485e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>