Kill all queued jenkins jobs and cancel any running jobs

clear_build_history.groovy

Jenkins.instance.getView('All').getBuilds().each { it.delete() }

clear_queue.groovy

import hudson.model.*

def q = Jenkins.instance.queue

// Cancel queued
q.items.each { q.cancel(it.task) }

// Stop running
Jenkins.instance.getView('All').getBuilds().findAll() { it.getResult().equals(null) }.each{
  println("Stopping job ${it}")
  it.doStop()
}