Check all ancestor navigable trustworthiness for mixed content (#36157)

Propagate through documents a flag that represents if any of the
ancestor navigables has a potentially trustworthy origin.

The "potentially trustworthy origin" concept appears to have gotten
confused in a couple of places and we were instead testing if a URL had
"potentially trustworthy" properties.

The main test for the ancestor navigables is
[mixed-content/nested-iframes](https://github.com/web-platform-tests/wpt/blob/master/mixed-content/nested-iframes.window.js)

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- [X] These changes fix #36108 

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Signed-off-by: Sebastian C <sebsebmc@gmail.com>

tests/wpt/meta/secure-contexts/shared-worker-secure-first.https.html.ini

@@ -1,4 +1,5 @@
 [shared-worker-secure-first.https.html]
+  expected: TIMEOUT
   [Shared worker in subframe]
     expected: FAIL
 
@@ -6,7 +7,7 @@
     expected: FAIL
 
   [Shared worker in popup]
-    expected: FAIL
+    expected: NOTRUN
 
   [Nested worker from shared worker in popup]
-    expected: FAIL
+    expected: NOTRUN