Test: Add more helper functions for private DNS validation events am:...

Test: Add more helper functions for private DNS validation events am: 7656f200 am: 71fe7845 am: 210f163d am: 0828c192

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/2685926



Change-Id: I18d847f6e5dff1f6d9ecd98e17af50b0777c8a46
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>