Tests: Move autoloader into correct folder. (#1055)

Follow up to #1051.

Author: obenland

tests/class-test-autoloader.php tests/includes/class-test-autoloader.phptests/class-test-autoloader.php renamed to tests/includes/class-test-autoloader.php

@@ -69,7 +69,7 @@ public function test_register_path() {
 	 * @covers ::load
 	 */
 	public function test_load() {
-		$autoloader = new Autoloader( __NAMESPACE__, __DIR__ );
+		$autoloader = new Autoloader( __NAMESPACE__, dirname( __DIR__ ) );
 
 		// Wrong prefix.
 		$autoloader->load( 'Activitypub\Autoload_Test_File' );