This is a testharness.js-based test.
[FAIL] Upgrade in tree order in the same tree scope
Illegal constructor
[FAIL] Upgrade in shadow-including tree order across tree scopes
Illegal constructor
[FAIL] Upgrade order does not depend on shadow root attach order
Illegal constructor
[FAIL] Upgrade in association order across documents, then tree order in each document
Illegal constructor
[FAIL] Upgrade order is not affected by DOM order between child frames
Illegal constructor
[FAIL] Upgrade order is affected by shadow tree adoption across documents
Illegal constructor
[FAIL] Elements in the "owner" window of a scoped registry are not always upgraded first
Illegal constructor
Harness: the test ran to completion.