This is a testharness.js-based test.
[FAIL] Prefetch should fire the load event for 404
  assert_equals: expected "load" but got "error"
[FAIL] Prefetch should fire the load event for 404 (cross-origin)
  assert_equals: expected "load" but got "error"
[FAIL] Prefetch should fire the load event for 500
  assert_equals: expected "load" but got "error"
[FAIL] Cross-origin prefetch should fire the load event for 500
  assert_equals: expected "load" but got "error"
Harness: the test ran to completion.