Update the .bp file and the skeleton of ArtServiceTests.

- Change the test to `android_test`, which is commonly used for mainline
  module unit tests. (`java_test` doesn't work with Mockito, which is an
  essential library for unit testing. It may also cause other problems
  in the future.)
- Specify sdk_version and min_sdk_version.
- Migrate the test to using Mockito JUnit test runner.
- Migrate the test to using Truth.

Bug: 177273468
Test: atest ArtServiceTests
Ignore-AOSP-first: Will cherry-pick later.
Change-Id: I7c25b3cf95b6fd5ee7d749bf08cfdd8c41ba89c9
3 files changed