Auto merge of #11476 - asajeffrey:add-tests-for-iframe-parentage, r=jdm

Added wpt tests for same-origin iframe parentage.

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Added some wpt tests to make sure same-origin iframes have the right parentage.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] There are tests for these changes OR

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tests/wpt/mozilla/meta/MANIFEST.json

@@ -6454,6 +6454,12 @@
             "url": "/_mozilla/mozilla/iframe-unblock-onload.html"
           }
         ],
+        "mozilla/iframe/same_origin_parentage.html": [
+          {
+            "path": "mozilla/iframe/same_origin_parentage.html",
+            "url": "/_mozilla/mozilla/iframe/same_origin_parentage.html"
+          }
+        ],
         "mozilla/iframe_contentDocument.html": [
           {
             "path": "mozilla/iframe_contentDocument.html",