Jenkinsfile: use mergeJunitResults() (#38313)

Jenkinsfile

@@ -25,7 +25,7 @@ pipeline {
                             'index.html', 'htmlcov-coverage-passerelle', 'Coverage passerelle tests')
                         utils.publish_pylint('pylint.out')
                     }
-                    junit 'junit-*.xml'
+                    mergeJunitResults()
                 }
             }
         }