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

[automerger skipped] Fix use-after-free in DNS64 discovery thread am: 79f57106 -s ours am: 51b15873 -s ours

am skip reason: Merged-In I3445f9ccdbb9746c0f78ad8b50e3193c6a1868a3 with SHA-1 581636ab is already in history

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



Change-Id: I99885e5571d833dae41d7281f1da2235993edd7f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>