This is a testharness.js-based test.
[FAIL] HTMLElement constructor must not get .prototype until it finishes its extends sanity checks, calling proxy constructor directly
  assert_equals: Should never have gotten .prototype expected 0 but got 1
[FAIL] HTMLElement constructor must not get .prototype until it finishes its extends sanity checks, calling via Reflect
  assert_equals: Should never have gotten .prototype expected 0 but got 1
Harness: the test ran to completion.