
PASS autonomous: document.importNode() should import custom elements successfully 
PASS autonomous: document.importNode() should import "undefined" custom elements successfully 
FAIL built-in: document.importNode() should import custom elements successfully promise_test: Unhandled rejection with value: object "TypeError: The superclass is not a constructor."
FAIL built-in: document.importNode() should import "undefined" custom elements successfully promise_test: Unhandled rejection with value: object "TypeError: The superclass is not a constructor."