Various linter fixes

Summary:
Fixed various linter issues that were identified by running `arc lint --everything`.

- Removed trailing whitespace.
- Added newline at EOF.
- Added whitespace after `if` statement

Test Plan: N/A

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: aurelijus, Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8337

src/unit/engine/PhpunitTestEngine.php

@@ -58,7 +58,7 @@ final class PhpunitTestEngine extends ArcanistBaseUnitTestEngine {
     $futures = array();
     $tmpfiles = array();
     foreach ($this->affectedTests as $class_path => $test_path) {
-      if(!Filesystem::pathExists($test_path)) {
+      if (!Filesystem::pathExists($test_path)) {
         continue;
       }
       $json_tmp = new TempFile();