Before this pr, we get this in linux:
```
$ make test
Running tests for APIVersion: v1,admissionregistration.k8s.io/v1alpha1,admissionregistration.k8s.io/v1beta1,admission.k8s.io/v1beta1,apps/v1beta1,apps/v1beta2,apps/v1,authentication.k8s.io/v1,authentication.k8s.io/v1beta1,authorization.k8s.io/v1,authorization.k8s.io/v1beta1,autoscaling/v1,autoscaling/v2beta1,batch/v1,batch/v1beta1,batch/v2alpha1,certificates.k8s.io/v1beta1,extensions/v1beta1,events.k8s.io/v1beta1,imagepolicy.k8s.io/v1alpha1,networking.k8s.io/v1,policy/v1beta1,rbac.authorization.k8s.io/v1,rbac.authorization.k8s.io/v1beta1,rbac.authorization.k8s.io/v1alpha1,scheduling.k8s.io/v1alpha1,settings.k8s.io/v1alpha1,storage.k8s.io/v1beta1,storage.k8s.io/v1,storage.k8s.io/v1alpha1,
+++ [0224 16:10:13] Running tests without code coverage
can't load package: package k8s.io/kubernetes/pkg/kubelet/winstats: build constraints exclude all Go files in /home/fujitsu/go/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/kubelet/winstats
!!! [0224 16:10:15] Call tree:
!!! [0224 16:10:15] 1: hack/make-rules/test.sh:402 runTests(...)
Makefile:182: recipe for target 'test' failed
make: *** [test] Error 1
```
This implements stats for windows nodes in a new package, winstats.
WinStats exports methods to get cadvisor like datastructures, however
with windows specific metrics. WinStats only gets node level metrics and
information, container stats will go via the CRI. This enables the
use of the summary api to get metrics for windows nodes.
Cao Shufeng