* FACEs work, setFormValue test is awful so now has _mozilla backup
* 1. Impl Validatable in ElementInternals instead of HTMLElement. 2. Reuse the code in Validatable trait. 3. The form associated custom element is not a customized built-in element.
* add some comments
* support readonly attribute and complete barred from constraint validation
* Addressed the code review comments
* Updated the legacy-layout results
* Fixed the WPT failures in ElementInternals-validation.html
* Addressed the code review comments
* Review suggestions
* Fixed silly mistakes and update the test result outside elementinternals
* update the test results
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Co-authored-by: Patrick Shaughnessy <pshaughn@comcast.net>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>
