Fix(testing): Register shutdown handler to delete temp input file

- Register shutdown function to delete the temporary input file via FileSystem::delete
- Avoid leftover test artifacts by removing fixture-derived files on process exit
- Return $inputFilePath and ensure it is cleaned up after tests

Author: guanguans

src/Testing/PHPUnit/AbstractRectorTestCase.php

@@ -296,6 +296,9 @@ private function createInputFilePath(string $fixtureFilePath): string
         }
 
         $fixtureBasename = pathinfo($trimmedFixtureFilePath, PATHINFO_BASENAME);
-        return $inputFileDirectory . '/' . $fixtureBasename;
+        $inputFilePath = $inputFileDirectory . '/' . $fixtureBasename;
+        register_shutdown_function([FileSystem::class, 'delete'], $inputFilePath);
+
+        return $inputFilePath;
     }
 }