Automatic merge from submit-queue (batch tested with PRs 45996, 46121, 45707, 46011, 45564)
Fix kuberuntime GetPods.
The `ImageID` is not populated from `GetPods` in kuberuntime.
Image garbage collector is using this field, https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/images/image_gc_manager.go#L204.
Without this fix, image garbage collector will try to garbage collect all images every time. Because docker will not allow that, it should be fine. However, I'm not sure whether the unnecessary remove will cause any problem, e.g. overload docker image management system and make docker hang.
@dchen1107 @yujuhong @feiskyer Do you think we should cherry-pick this?