Sort files to avoid breaking tests

Author: polothy

src/Installer/TestSuiteInstaller.php

@@ -198,7 +198,8 @@ private function getCoverageFiles()
             ->notName('version.php')
             ->notName('settings.php')
             ->notPath('lang')
-            ->notPath('vendor');
+            ->notPath('vendor')
+            ->sortByName();
 
         $this->plugin->context = 'phpunit'; // Bit of a hack, but ensure we respect PHPUnit ignores.