improve burncpu in k8s-pod

[wayne-pq]

when i use burncpu in k8s-pod, cpu-percent is useless, but chaosmess work well. please improve burncpu in k8s-pod

• chaosmess specify 50% cpu-percent (limit 2c):

apiVersion: chaos-mesh.org/v1alpha1
kind: StressChaos
metadata:
  name: burn-cpu
  namespace: chaos-testing
spec:
  mode: one
  selector:
    labelSelectors:
       "app.kubernetes.io/instance": "10015-deployment-uat-10700"
    namespaces:
      - default
  stressors:
    cpu:
      workers: 2
      load: 50
  duration: "120s"
  scheduler:
    cron: "@every 5m"