Add artd unit tests. am: 9f4e1f04b5

Original change: https://android-review.googlesource.com/c/platform/art/+/2129473

Change-Id: I952d9d319c54143b4994ac0a24305d576b52440b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>