Disable Windows Defender in Windows nodes on GCE again.

This reverts commit fbf4fe4714. Windows
Defender seems to be causing our Windows nodes to crash and reboot
during e2e tests, e.g.
https://gcsweb.k8s.io/gcs/kubernetes-jenkins/logs/ci-kubernetes-e2e-windows-gce/228/artifacts/e2e-228-36623-windows-node-group-q4.

cluster/gce/windows/configure.ps1

@@ -100,6 +100,7 @@ try {
   Dump-DebugInfoToConsole
   Set-PrerequisiteOptions
   $kube_env = Fetch-KubeEnv
+  Disable-WindowsDefender
 
   if (Test-IsTestCluster $kube_env) {
     Log-Output 'Test cluster detected, installing OpenSSH.'