https://xhr.spec.whatwg.org/#the-responseurl-attribute
the attribute was introduced around 2014.
[ChangeLog][Qml][XMLHttpRequest] Added missing responseURL property. This returns the url that was used to retrieve the response data, after any redirects have occurred.
Change-Id: Ice70520913bb306885a10dfd7a3a89da31bcfdeb
Task-number: QTBUG-111217
Reviewed-by: Lars Knoll <lars@knoll.priv.no>