Prevent failing filter handling on 'Test' instances

Make sure the 'processSuiteFilters' method is only called for
'TestSuite' objects not for 'Test' objects.
To achieve this, the 'processSuiteFilters' method call got
moved to an existing type check.

Fix issue sebastianbergmann#3254

src/TextUI/TestRunner.php

@@ -190,8 +190,6 @@ public function doRun(Test $suite, array $arguments = [], $exit = true)
 
         $this->handleConfiguration($arguments);
 
-        $this->processSuiteFilters($suite, $arguments);
-
         if (isset($arguments['bootstrap'])) {
             $GLOBALS['__PHPUNIT_BOOTSTRAP'] = $arguments['bootstrap'];
         }
@@ -540,6 +538,7 @@ public function doRun(Test $suite, array $arguments = [], $exit = true)
         $result->setTimeoutForLargeTests($arguments['timeoutForLargeTests']);
 
         if ($suite instanceof TestSuite) {
+            $this->processSuiteFilters($suite, $arguments);
             $suite->setRunTestInSeparateProcess($arguments['processIsolation']);
         }