Add first order deps to test build file

We should have our first order dependencies specified in our build
file to help aidegen ensure that any generated IDE files aren't
missing crucial dependencies.

In this case adding mockito and truth allows IntelliJ to show the
verify(...) and assertThat(....) calls are valid and not leave them
as red-underlined undefinied calls.

Test: aidegen frameworks/base/services/robotests/backup/
Change-Id: Iea347c623dc0bbe5740d6129e710b4757c87d781