Mark PHPUnit test as not performing any assertion

Summary:
This test is complete, as it's intended to detect the code copes with
a non existing project, without throwing an exception.

This is a follow-up for 327396a7.

Test Plan: phpunit

Reviewers: DorianWinty

Reviewed By: DorianWinty

Differential Revision: https://devcentral.nasqueron.org/D2964