[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: 5e212f10 -s ours am: c4ef2f8d -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: I0ba5dcc05ad4c4311018d31c4310a66e1b35679f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>