Tests the signed exchange information are available when the certificate file is not available.

about:blank:1 Invalid reponse code: 404
about:blank:1 Failed to fetch the certificate.
* http://127.0.0.1:8000/loading/sxg/resources/sxg-cert-not-found.sxg
  failed: false
  statusCode: 200
  resourceType: signed-exchange
  SignedExchangeInfo
    Request URL: https://127.0.0.1:8443/loading/sxg/resources/inner-url.html
    Certificate URL: https://127.0.0.1:8443/loading/sxg/resources/not_found_cert.pem.cbor
    Error: {"message":"Invalid reponse code: 404"}
    Error: {"message":"Failed to fetch the certificate.","signatureIndex":0,"errorField":"signatureCertUrl"}
* https://127.0.0.1:8443/loading/sxg/resources/not_found_cert.pem.cbor
  failed: true
  statusCode: 404
  resourceType: other
* https://127.0.0.1:8443/loading/sxg/resources/inner-url.html
  failed: false
  statusCode: 200
  resourceType: document