[automerger skipped] Fix use-after-free in DNS64 discovery thread am:...

[automerger skipped] Fix use-after-free in DNS64 discovery thread am: cad5a8c8 am: 4d92807d -s ours am: 24606ea8 -s ours am: 000ca742 -s ours am: a1e66cce -s ours am: 09d0b260 -s ours

am skip reason: Merged-In Id74ea4e6f54a00805d3cc8a9d7e15e58a473b7d3 with SHA-1 292b59e1 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/24365338



Change-Id: I69334940e856e3a179f291e4ada2149cc8dc3e28
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>