Add RebootTargetPreparer for tests that require root permission am: 37a894be am: d5369624

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/2323393



Change-Id: I4a71bfb98457125e42f38bb4f0f57fec702108dd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>