
PASS Element.prototype.createElement must add an unresolved custom element to the upgrade candidates map 
PASS HTMLElement constructor must throw an TypeError when the top of the construction stack is marked AlreadyConstructed due to a custom element constructor constructing itself after super() call 
PASS HTMLElement constructor must throw an TypeError when the top of the construction stack is marked AlreadyConstructed due to a custom element constructor constructing itself before super() call 
PASS Upgrading a custom element must throw an TypeError when the returned element is not SameValue as the upgraded element 
PASS Upgrading a custom element whose constructor returns a Text node must throw 
PASS Upgrading a custom element whose constructor returns an Element must throw