Stop blocking 'http://127.0.0.1/' as mixed content.

third_party/WebKit/LayoutTests/http/tests/security/mixedContent/resources/frame-with-insecure-async-xhr-post.html

 <script>
 function report(message) {
   window.opener.postMessage(message, '*');
 }
 
 var xhr = new XMLHttpRequest();
 xhr.onload = function() {
   report('FAIL: XHR succeeded unexpectedly');
 }
 xhr.onerror = function() {
   report('DONE');
 };
-xhr.open("POST", "http://127.0.0.1:8000/xmlhttprequest/resources/access-control-allow-lists.php?origin=*", true);
+xhr.open("POST", "http://example.test:8000/xmlhttprequest/resources/access-control-allow-lists.php?origin=*", true);
 xhr.send("foo");
 </script>