Fix newly introduced test for Windows

The warning message is rather different there, but since that is
irrelevant for this test case, we just suppress the warning.

Author: cmb69

ext/mysqli/tests/mysqli_incomplete_initialization.phpt

@@ -8,13 +8,11 @@ require_once('skipif.inc');
 <?php
 
 $mysqli = new mysqli();
-$mysqli->__construct(null);
+@$mysqli->__construct(null);
 $mysqli->close();
 
 ?>
 --EXPECTF--
-Warning: mysqli::__construct(): (HY000/2002): No such file or directory in %s on line %d
-
 Fatal error: Uncaught Error: mysqli object is not fully initialized in %s:%d
 Stack trace:
 #0 %s(%d): mysqli->close()