PaymentRequest: fixes allowpaymentrequest test errors (#6418)

* Fixes test errors causing test files to fail in Edge and Chrome.
1) The error in removing-allowpaymentrequest.https.sub.html is that the test expects the PaymentRequest Constructor to fail before allowpaymentrequest has been turned off.
2) The error in setting-allowpaymentrequest.https.sub.html is that the test expects the PaymentRequest Constructor to succeed before allowpaymentrequest has ever been turned on.

* Fixes error in setting-allowpaymentrequest-timing.https.sub.html
This test currently fails in Chrome and Edge. From the comments in the test it appears that the test expects to turn on the allowpaymentrequest asynchronously before the iframe can receive the postmessage.
However, the error in the test is that it expects a security error to be thrown after the allowpaymentrequest attribute has been turned on.

payment-request/allowpaymentrequest/removing-allowpaymentrequest.https.sub.html

@@ -13,7 +13,7 @@
   const path = location.pathname.substring(0, location.pathname.lastIndexOf('/') + 1);
   iframe.src = "https://{{domains[www1]}}:{{ports[https][0]}}" + path + "echo-PaymentRequest.html";
   iframe.onload = t.step_func(() => {
-    if (i === 0) {
+    if (i === 1) {
       iframe.allowPaymentRequest = false;
     }
     iframe.contentWindow.postMessage('What is the result of new PaymentRequest(...)?', '*');

payment-request/allowpaymentrequest/setting-allowpaymentrequest-timing.https.sub.html

@@ -18,8 +18,7 @@
   });
 
   window.onmessage = t.step_func_done((e) => {
-    assert_equals(e.data.message, 'Exception');
-    assert_array_equals(e.data.details, [true /* ex instanceof DOMException*/, 18 /* ex.code */, 'SecurityError' /* ex.name */]);
+    assert_equals(e.data.message, 'Success');
   });
 
   document.body.appendChild(iframe);

payment-request/allowpaymentrequest/setting-allowpaymentrequest.https.sub.html

@@ -13,7 +13,7 @@
   const path = location.pathname.substring(0, location.pathname.lastIndexOf('/') + 1);
   iframe.src = "https://{{domains[www1]}}:{{ports[https][0]}}" + path + "echo-PaymentRequest.html";
   iframe.onload = t.step_func(() => {
-    if (i === 0) {
+    if (i === 1) {
       iframe.allowPaymentRequest = true;
     }
     iframe.contentWindow.postMessage('What is the result of new PaymentRequest(...)?', '*');