Auto merge of #25446 - pshaughn:fixme11868, r=jdm

Make getOwnPropertyDescriptor hold the correct value for indexed/named properties

This is towards #25036 and #25415; it could have far-reaching implications so I want to test it in isolation and see the results on the full test suite.

A few lines of code had a FIXME(#11868) despite that issue being closed, and looking for the pattern that was marked that way, I found one other unmarked instance of it. It doesn't immediately crash, and maybe it will pass some tests or fail some tests in informative ways.

EDIT: After adding an overlooked extended attribute to HTMLFormElement, this works very well indeed and seems to be worth merging!

---
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- [X] These changes fix #25036

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tests/wpt/metadata/WebIDL/ecmascript-binding/legacy-platform-object.html.ini

@@ -1,14 +1,5 @@
 [legacy-platform-object.html]
   type: testharness
-  [[[GetOwnProperty\]\] with getters and no setters]
-    expected: FAIL
-
-  [[[GetOwnProperty\]\] with named property getters and setters]
-    expected: FAIL
-
-  [[[GetOwnProperty\]\] with indexed property getters and setters]
-    expected: FAIL
-
   [Test [[DefineOwnProperty\]\] with no indexed property setter support.]
     expected: FAIL
 

tests/wpt/metadata/dom/collections/HTMLCollection-supported-property-indices.html.ini

@@ -6,6 +6,3 @@
   [Trying to set an expando with an indexed property name past the end of the list]
     expected: FAIL
 
-  [Trying to delete an indexed property name should never work]
-    expected: FAIL
-

tests/wpt/metadata/html/dom/elements/global-attributes/dataset-binding.window.js.ini

@@ -5,9 +5,3 @@
   [Setting property for key 9 with accessor property on prototype]
     expected: FAIL
 
-  [Getting property descriptor for key 9]
-    expected: FAIL
-
-  [Getting property descriptor for key x]
-    expected: FAIL
-

tests/wpt/metadata/html/semantics/forms/the-form-element/form-nameditem.html.ini

@@ -1,8 +1,5 @@
 [form-nameditem.html]
   type: testharness
-  [Name for a single element should work]
-    expected: FAIL
-
   [All listed elements except input type=image should be present in the form]
     expected: FAIL