Windows: Fixes termination-file mounting for containerd

If Containerd is used on Windows, then we can also mount individual
files into containers (e.g.: termination-log files), which was not
possible with Docker.

Checks if the container runtime is containerd, and if it is, then also
mount the termination-log file.

pkg/kubelet/container/testing/fake_runtime.go

@@ -177,6 +177,10 @@ func (f *FakeRuntime) Type() string {
 	return f.RuntimeType
 }
 
+func (f *FakeRuntime) SupportsSingleFileMapping() bool {
+	return true
+}
+
 func (f *FakeRuntime) Version() (kubecontainer.Version, error) {
 	f.Lock()
 	defer f.Unlock()

pkg/kubelet/container/testing/runtime_mock.go

@@ -47,6 +47,11 @@ func (r *Mock) Type() string {
 	return args.Get(0).(string)
 }
 
+func (r *Mock) SupportsSingleFileMapping() bool {
+	args := r.Called()
+	return args.Get(0).(bool)
+}
+
 func (r *Mock) Version() (kubecontainer.Version, error) {
 	args := r.Called()
 	return args.Get(0).(kubecontainer.Version), args.Error(1)