Auto merge of #12847 - clstl:HTMLDialogElement#close, r=nox

Implements HTMLDialogElement#close

<!-- Please describe your changes on the following line: -->
Implements HTMLDialogElement#close according to [link](https://html.spec.whatwg.org/multipage/#the-dialog-element:dom-dialog-close)

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #12352
- [X] There are tests for these change

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tests/wpt/metadata/html/dom/interfaces.html.ini

@@ -4374,9 +4374,6 @@
   [HTMLDialogElement interface: operation showModal([object Object\],[object Object\])]
     expected: FAIL
 
-  [HTMLDialogElement interface: operation close(DOMString)]
-    expected: FAIL
-
   [HTMLScriptElement interface: attribute async]
     expected: FAIL
 

tests/wpt/metadata/html/semantics/interactive-elements/the-dialog-element/dialog-close.html.ini

@@ -1,17 +1,5 @@
 [dialog-close.html]
   type: testharness
-  [close() fires a close event]
-    expected: FAIL
-
   [close() on a <dialog> that doesn't have an open attribute throws an InvalidStateError exception]
     expected: FAIL
 
-  [close() removes the open attribute and set the returnValue to the first argument]
-    expected: FAIL
-
-  [close() without argument removes the open attribute and there's no returnValue]
-    expected: FAIL
-
-  [close() should set the returnValue IDL attribute but not the JS property]
-    expected: FAIL
-

tests/wpt/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-close.html

@@ -36,10 +36,9 @@
       was_queued = false;
 
   test(function(){
-    assert_throws("INVALID_STATE_ERR", function() {
-      d1.close();
-    });
-  }, "close() on a <dialog> that doesn't have an open attribute throws an InvalidStateError exception");
+    d1.close("closedialog");
+    assert_equals(d1.returnValue, "");
+  }, "close() on a <dialog> that doesn't have an open attribute aborts the steps");
 
   test(function(){
     assert_true(d2.open);