Kill all build and remove queued ones

killAllBuilds.groovy

import java.util.ArrayList;
import hudson.model.*;

def q = Jenkins.instance.queue
for (queued in Jenkins.instance.queue.items) {
    q.cancel(queued.task)
}

for (job in Jenkins.instance.items) {
    stopJobs(job)
}

def stopJobs(job) {
    if (job in com.cloudbees.hudson.plugins.folder.Folder) {
        for (child in job.items) {
            stopJobs(child)
        }
    } else if (job in org.jenkinsci.plugins.workflow.multibranch.WorkflowMultiBranchProject) {
        for (child in job.items) {
            stopJobs(child)
        }
    } else if (job in org.jenkinsci.plugins.workflow.job.WorkflowJob) {
        if (job.isBuilding()) {
            for (build in job.builds) {
                build.doKill()
            }
        }
    }
}