ci: remove Jenkinsfile to test branch exclusion

Jenkinsfile

@@ -1,33 +0,0 @@
-pipeline {
-  agent any
-  options { timeout(time: 60, unit: 'SECONDS') }
-  stages {
-    stage('Checkout and identify change') {
-      steps {
-        checkout scm
-        echo "BRANCH_NAME=${env.BRANCH_NAME ?: ''}"
-        echo "CHANGE_ID=${env.CHANGE_ID ?: ''}"
-        echo "CHANGE_TARGET=${env.CHANGE_TARGET ?: ''}"
-        script {
-          def scenario = readFile('ci/scenario.txt').trim()
-          if (!(scenario in ['success', 'unstable', 'failure'])) {
-            error("Unsupported demo scenario: ${scenario}")
-          }
-          env.SCENARIO = scenario
-        }
-      }
-    }
-    stage('Build and report') {
-      steps {
-        script {
-          int status = sh(script: 'sh ci/demo-build.sh', returnStatus: true)
-          junit 'reports/*.xml'
-          if (status != 0) error("Demo build exited with status ${status}")
-        }
-      }
-    }
-  }
-  post {
-    always { archiveArtifacts artifacts: 'artifacts/*', allowEmptyArchive: true }
-  }
-}