Add artd unit tests. am: 9f4e1f04b5 am: 983dca9497

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

Change-Id: I6ef317433b24e192b18c89733e3c4c02d6c1cbf2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>