Merge "[DRUEL02] Add registerUnsolicitedEventListener test" am: 3b0d79f2 am: 9eb8ce96 am: 7fef5cb7

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/1501890

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ia6a6cbae49f99c6c1ccc29e2c5e4ff453d3871c6