Utilize `assertFalse` and `assertTrue` methods.

Summary:
Ref D8460.

Use $this->assertFalse(...) and $this->assertTrue(...) instead of $this->assertEqual(false, ...) and $this->assertEqual(true, ...) respectively.

Test Plan: `arc unit`

Reviewers: epriestley, #blessed_reviewers

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8462