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

[automerger skipped] Fix use-after-free in DNS64 discovery thread am: 79f57106 am: d5fafcf0 -s ours am: 734708a2 -s ours am: 2b2e91bd -s ours am: f63a9bd6 -s ours am: aabdeb33 -s ours

am skip reason: Merged-In Id74ea4e6f54a00805d3cc8a9d7e15e58a473b7d3 with SHA-1 87676fe7 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/24545343



Change-Id: Iab7be2189d6527ec516d8354a193c2cdd5755366
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>