Make test_required_files.py real unit tests

Change-Id: I0af14c6d9147d388a579d9586eefccd73fd7aab8
Cleanup tests

Move test code into tests.
Remove last_failures test, as its replaced by other tests now.
Remove dead code.

Change-Id: I3514f62e003b1140fbe597cc91aea3089c268ac7
Merge "Cleanup tests"
Merge "Make test_required_files.py real unit tests"