Add k8s 1.13.4 GCE PD CSI Driver test sku
Add k8s 1.13.4 GCE PD CSI Driver test sku

GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid