[Misc] All overrun on master CI. (#5360)

* exclude_master

* fix

---------
Co-authored-by: Ubuntu <ubuntu@ip-172-31-28-63.ap-northeast-1.compute.internal>

Jenkinsfile

@@ -240,9 +240,10 @@ pipeline {
         stage('Abort Previous CI') {
           steps {
             script {
+              if (env.BRANCH_NAME != "master") {
+                // Jenkins will abort an older build if a newer build already
+                // passed a higher milestone.
                 // https://www.jenkins.io/doc/pipeline/steps/pipeline-milestone-step/
-              // Note: incorrect "success" status might be shown for the old
-              // runs in the PR.
                 def buildNumber = env.BUILD_NUMBER as int
                 for (int i = 1; i <= buildNumber; i++) {
                   milestone(i)
@@ -250,6 +251,7 @@ pipeline {
               }
             }
           }
+        }
 
         stage('Lint Check') {
           agent {