Node e2e export test artifacts to jenkins.

- Add junit test reported
- Write etcd.log, kubelet.log and kube-apiserver.log to files instead of stdout
- Scp artifacts to the jenkins WORKSPACE

Fixes #25966

hack/verify-flags/known-flags.txt

@@ -201,6 +201,7 @@ ir-password
 ir-user
 jenkins-host
 jenkins-jobs
+junit-file-number
 k8s-bin-dir
 k8s-build-output
 keep-gogoproto
@@ -366,6 +367,7 @@ resolv-conf
 resource-container
 resource-quota-sync-period
 resource-version
+results-dir
 retry_time
 rkt-api-endpoint
 rkt-path