Specify sequence of navigation failure checks

The clause "if any of the following are true" does not indicate the
intended sequence by which the subsequent conditions must be evaluated.
Conforming implementations are therefore free to perform the checks in
any order. However, the sequence is observable by web content because
both the Content-Security Policy (CSP) check and the Cross-Origin
Embedder Policy (COEP) check may trigger reporting events.

The current implementation status is as follows (neither Safari nor
Firefox implement COEP reporting at this time):

- Chrome 86:   CSP, then COEP, then X-Frame-Options
- Firefox 80:  CSP, then X-Frame-Options
- Safari 13.1: CSP, then X-Frame-Options

Standardize the sequence according to the state of the implementations.

source

@@ -83163,30 +83163,33 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
    <li><p>Let <var>browsingContext</var> be <var>navigationParams</var>'s <span
    data-x="navigation-params-browsing-context">browsing context</span>.</p></li>
 
+   <li><p>Let <var>failure</var> be false.</p></li>
+
    <li>
-    <p>If any of the following are true:</p>
+    <p>If <var>response</var> is a <span>network error</span>, then set <var>failure</var> to
+    true.</p>
 
-    <ul>
-     <li><p><var>response</var> is a <span>network error</span>;</p></li>
-
-     <li><p>the result of <span>should navigation response to navigation request of type from source
-     in target be blocked by Content Security Policy?</span> given <var>navigationParams</var>'s
-     <span data-x="navigation-params-request">request</span>, <var>response</var>,
-     <var>navigationType</var>, <var>source</var>, and <var>browsingContext</var> is "<code
-     data-x="">Blocked</code>"; <ref spec="CSP"></p></li>
-
-     <li><p>the result of <span data-x="check a navigation response's adherence to
-     `X-Frame-Options`">checking a navigation response's adherence to
-     `<code>X-Frame-Options</code>`</span> given <var>response</var>, <var>browsingContext</var>,
-     and <var>navigationParams</var>'s <span data-x="navigation-params-origin">origin</span> is
-     false; or</p></li>
-
-     <li><p>the result of <span data-x="check a navigation response's adherence to its embedder
-     policy">checking a navigation response's adherence to its embedder policy</span> given
-     <var>response</var> and <var>browsingContext</var> is false.</p></li>
-    </ul>
+    <p>Otherwise, if the result of <span>should navigation response to navigation request of type
+    from source in target be blocked by Content Security Policy?</span> given
+    <var>navigationParams</var>'s <span data-x="navigation-params-request">request</span>,
+    <var>response</var>, <var>navigationType</var>, <var>source</var>, and
+    <var>browsingContext</var> is "<code data-x="">Blocked</code>", then set <var>failure</var> to
+    true. <ref spec="CSP"></p>
 
-    <p>then:</p>
+    <p>Otherwise, if the result of <span data-x="check a navigation response's adherence to its
+    embedder policy">checking a navigation response's adherence to its embedder policy</span> given
+    <var>response</var> and <var>browsingContext</var> is false, then set <var>failure</var> to
+    true.</p>
+
+    <p>Otherwise, if the result of <span data-x="check a navigation response's adherence to
+    `X-Frame-Options`">checking a navigation response's adherence to
+    `<code>X-Frame-Options</code>`</span> given <var>response</var>, <var>browsingContext</var>,
+    and <var>navigationParams</var>'s <span data-x="navigation-params-origin">origin</span> is
+    false, then set <var>failure</var> to true.</p>
+   </li>
+
+   <li>
+    <p>If <var>failure</var> is true, then:</p>
 
     <ol>
      <li><p><span data-x="navigate-ua-inline">Display the inline content with an appropriate error