Made Android linter run on entire project

Summary: The Android linter was running on individual files, so it wasn't catching many things. It now runs on entire projects.

Test Plan: Change a file in an Android project and run `arc lint`. You should see lint warnings or errors from files that were not changed.

Reviewers: mbishop

Reviewed By: mbishop

Maniphest Tasks: T3591

Differential Revision: https://devportal.imobile3.com/D3498