Assert all test files are cleaned up in CI

Closes phpGH-8427

Author: iluuu1994

.github/actions/verify-generated-files/action.yml

@@ -11,4 +11,4 @@ runs:
         build/gen_stub.php -f
         build/gen_stub.php --generate-optimizer-info
         ext/tokenizer/tokenizer_data_gen.php
-        git add . -Nu && git diff --exit-code
+        git add . -N && git diff --exit-code

ext/spl/tests/SplFileObject/fileobject_005.phpt

@@ -6,12 +6,10 @@ Mark Ammann
 --FILE--
 <?php
 
-set_include_path(dirname(__DIR__));
-
 $path = __DIR__.DIRECTORY_SEPARATOR.'fileobject_005.txt';
 touch($path);
 
-$fo = new SplFileObject('tests'.DIRECTORY_SEPARATOR.'fileobject_005.txt', 'w+', true);
+$fo = new SplFileObject($path, 'w+', true);
 $fo->fwrite("blahlubba");
 var_dump($fo->ftruncate(4));