Remove now-unnecessary COOP-specific navigation redirect fix

This reverts most of commit 63e2f17 (except for a typo fix). Now that the more general issue is fixed (see #8740 and whatwg/fetch#1618), we no longer need to look at unsafe responses inside the navigate algorithm.

source

@@ -2595,7 +2595,6 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
        <li><dfn data-x="concept-response-timing-info" data-x-href="https://fetch.spec.whatwg.org/#concept-response-timing-info">timing info</dfn></li>
        <li><dfn data-x="concept-response-service-worker-timing-info" data-x-href="https://fetch.spec.whatwg.org/#response-service-worker-timing-info">service worker timing info</dfn></li>
        <li><dfn data-x="concept-response-has-cross-origin-redirects" data-x-href="https://fetch.spec.whatwg.org/#response-has-cross-origin-redirects">has-cross-origin-redirects</dfn></li>
-       <li><dfn data-x="concept-filtered-response-opaque-redirect" data-x-href="https://fetch.spec.whatwg.org/#concept-filtered-response-opaque-redirect">opaque-redirect filtered response</dfn></li>
        <li>
         <dfn data-x-href="https://wicg.github.io/background-fetch/#extract-content-range-values">extract content-range values</dfn>
         <!-- TODO: move this to FETCH -->
@@ -83709,8 +83708,7 @@ dictionary <dfn dictionary>ToggleEventInit</dfn> : <span>EventInit</span> {
 
    <li><p>Let <var>parsedItem</var> be the result of <span>getting a structured field value</span>
    given `<code>Cross-Origin-Opener-Policy</code>` and "<code data-x="">item</code>" from
-   <var>response</var>'s <span>unsafe response</span>'s <span
-   data-x="concept-response-header-list">header list</span>.</p>
+   <var>response</var>'s <span data-x="concept-response-header-list">header list</span>.</p></li>
 
    <li>
     <p>If <var>parsedItem</var> is not null, then:</p>