Configure existing WPP2 Robolectric tests to run with atest.

Also moves Robolectric tests into directory under tests/ for similar
structure to other test code in the wider codebase.

Bug: 260777356
Test: this is the test
Change-Id: Ie3190ccb9875cda80f5b576bf999bf71d8a25d53
Merged-In: Ie3190ccb9875cda80f5b576bf999bf71d8a25d53
7 files changed