Intermittent FAIL in /html/semantics/document-metadata/the-meta-element/pragma-directives/attr-meta-http-equiv-refresh/allow-scripts-flag-changing-2.html #39703

Stable unexpected results (1): 
  ▶ OK /html/semantics/document-metadata/the-meta-element/pragma-directives/attr-meta-http-equiv-refresh/allow-scripts-flag-changing-2.html
  │   ▶ FAIL [expected PASS] Meta refresh of the original iframe is not blocked if moved into a sandboxed iframe
  │   │   → uncaught exception: Error: assert_unreached: The iframe into which the meta was moved must not refresh Reached unreachable code
  │   │ 
  └   └ destIFrame.onload@http://web-platform.test:8000/html/semantics/document-metadata/the-meta-element/pragma-directives/attr-meta-http-equiv-refresh/allow-scripts-flag-changing-2.html:37:21