In https://github.com/jenkinsci/jenkins/pull/8840 a test timeout was increased to 500 seconds to work around an issue with the CI infrastructure (possibly artifact caching proxy?). Since the test should not take nearly that long (and does not, locally), this workaround should be removed once the underlying issue with the CI infrastructure is resolved. That underlying issue is being tracked in https://github.com/jenkins-infra/helpdesk/issues/3890.