Android: removed Robolectric 4.3.1 Buck configuration

Summary:
It was recently upgraded to 4.4, so we don't need the 4.3.1 anymore.

Changelog: [Android][Removed] Removed Robolectric 4.3.1 setup

Reviewed By: jselbo

Differential Revision: D24030822

fbshipit-source-id: 09b3c577d32028723e7bbc02f13459a7ae69b749

Author: fkgozali