Once JENKINS-49263 and JENKINS-49266 are done we need to incorporate the ATH step to the default jenkins core flow

Acceptance criteria

• Jenkins core runs the ATH test defined in JENKINS-49263 on every change in master branch and in any PR 
• The ATH step result is send to github as a status check via https://github.com/jenkinsci/pipeline-githubnotify-step-plugin
• The ATH status has no effect in the global pipeline status check