Use "process the next manual redirect" in navigation

This replaces our use "HTTP-redirect fetch", which was pretty broken. Follows whatwg/fetch#1469.

Co-authored-by: Domenic Denicola <[email protected]>

source

@@ -2542,7 +2542,6 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x-href="https://fetch.spec.whatwg.org/#concept-header-extract-mime-type">extract a MIME type</dfn></li>
      <li><dfn data-x-href="https://fetch.spec.whatwg.org/#legacy-extract-an-encoding">legacy extract an encoding</dfn></li>
      <li><dfn data-x="concept-fetch" data-x-href="https://fetch.spec.whatwg.org/#concept-fetch">fetch</dfn></li>
-     <li><dfn data-x-href="https://fetch.spec.whatwg.org/#concept-http-redirect-fetch">HTTP-redirect fetch</dfn></li>
      <li><dfn data-x-href="https://fetch.spec.whatwg.org/#ok-status">ok status</dfn></li>
      <li><dfn data-x="navigation-request" data-x-href="https://fetch.spec.whatwg.org/#navigation-request">navigation request</dfn></li>
      <li><dfn data-x-href="https://fetch.spec.whatwg.org/#concept-network-error">network error</dfn></li>
@@ -2555,6 +2554,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x="concept-header-list-set" data-x-href="https://fetch.spec.whatwg.org/#concept-header-list-set">set</dfn></li>
      <li><dfn data-x="concept-header-list-get-decode-split" data-x-href="https://fetch.spec.whatwg.org/#concept-header-list-get-decode-split">get, decode, and split</dfn></li>
      <li><dfn data-x="concept-fetch-terminate" data-x-href="https://fetch.spec.whatwg.org/#concept-fetch-terminate">terminate</dfn></li>
+     <li><dfn data-x-href="https://fetch.spec.whatwg.org/#process-the-next-manual-redirect">process the next manual redirect</dfn></li>
      <li><dfn data-x-href="https://fetch.spec.whatwg.org/#cross-origin-resource-policy-check">cross-origin resource policy check</dfn></li>
      <li>the <dfn data-x-href="https://fetch.spec.whatwg.org/#requestcredentials"><code>RequestCredentials</code></dfn> enumeration</li>
      <li>the <dfn data-x-href="https://fetch.spec.whatwg.org/#requestdestination"><code>RequestDestination</code></dfn> enumeration</li>
@@ -88912,6 +88912,8 @@ interface <dfn interface>Location</dfn> { // but see also <a href="#the-location
 
    <li><p>Let <var>commitEarlyHints</var> be null.</p></li>
 
+   <li><p>Let <var>fetchController</var> be null.</p></li>
+
    <li>
     <p>While true:</p>
 
@@ -89004,17 +89006,17 @@ interface <dfn interface>Location</dfn> { // but see also <a href="#the-location
       <p>Otherwise:</p>
 
       <ol>
-       <li><p>If <var>response</var> is null, <!--FETCH--><span
-       data-x="concept-fetch">fetch</span> <var>request</var>, with
+       <li><p>If <var>fetchController</var> is null, then set <var>fetchController</var> to the
+       result of <!--FETCH--><span data-x="concept-fetch">fetching</span> <var>request</var>, with
        <i data-x="processEarlyHintsResponse">processEarlyHintsResponse</i> set to the following step
        given a <span data-x="concept-response">response</span> <var>earlyResponse</var>: If
        <var>commitEarlyHints</var> is null, then set <var>commitEarlyHints</var> to the result
        of <span data-x="process early hint headers">processing early hint headers</span> given
        <var>earlyResponse</var> and <var>request</var>'s
        <span data-x="concept-request-reserved-client">reserved client</span>.</p></li>
 
-       <li><p>Otherwise, perform <span>HTTP-redirect fetch</span> using
-       <var>request</var> and <var>response</var>.</p></li>
+       <li><p>Otherwise, <span>process the next manual redirect</span> given
+       <var>fetchController</var>.</p></li>
 
        <li><p>Wait for the <span data-x="concept-task">task</span> on the <span>networking task
        source</span> to <span>process response</span> and set <var>response</var> to the