CORS: Handle error HTTP status code 4XX/5XX in preflight requests.

LayoutTests/http/tests/xmlhttprequest/resources/access-control-preflight-request-invalid-status.php

+<?php
+    $code = $_GET['code'];
+    $request_origin_value = $_SERVER["HTTP_ORIGIN"];
+    $access_control_request_headers = $_SERVER["HTTP_ACCESS_CONTROL_REQUEST_HEADERS"];
+
+    if ($_SERVER['REQUEST_METHOD'] == "OPTIONS") {
+        if ($code == "400") {
+            header("HTTP/1.1 400");
+        }
+        else if ($code == "501"){
+            header("HTTP/1.1 501");
+        }
+        header("Access-Control-Allow-Methods: GET");
+        header("Access-Control-Max-Age: 1");
+    } else {
+        header("HTTP/1.1 200");
+    }
+    if (!is_null($request_origin_value)) {
+        header("Access-Control-Allow-Origin: $request_origin_value");
+    }
+    if (!is_null($access_control_request_headers))
+        header("Access-Control-Allow-Headers: $access_control_request_headers");
+?>