Sanitizer: Always allow the new canonical form in allowElement.

Differential Revision: https://phabricator.services.mozilla.com/D266658

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1991098
gecko-commit: d8ce384e2a5154e1f98210ed44a483101bfe66cd
gecko-reviewers: smaug

Author: evilpie

sanitizer-api/sanitizer-modifiers.tentative.html

@@ -517,7 +517,7 @@
     replaceWithChildrenElements: []
   });
 
-  // If element["attributes"] or element["removeAttributes"] exists:
+  // If element["attributes"] exists or element["removeAttributes"] with default « » is not empty:
   //  The user agent may report a warning to the console that this operation is not supported.
   //  Return false.
   assert_false(s.allowElement({name: "a", attributes: ["dir"]}));
@@ -535,8 +535,7 @@
     removeElements: ["a"],
     replaceWithChildrenElements: []
   });
-
-  assert_true(s.allowElement("a"));
+  assert_true(s.allowElement({name: "a", removeAttributes: [] }));
   assert_config(s.get(), {
     removeElements: [],
     replaceWithChildrenElements: []