tests: Adds support for Windows cri-integration tests

Currently, the cri-integration tests do not work on Windows due to various reasons.
One of the reasons is because all the tests are using Linux-specific images.
Previous commits refactored the image pulling / usage in the cri-integration tests,
making it easier to update, and easier to configure a custom registry to pull images
with Windows support.

For Windows runs, custom registries can be created, which will also contain Windows
images, and the cri-integration tests can be configured to use those registries by
specifying the "--repo-list" argument, a YAML file which will contain an alternative
mapping of the default registries. This is similar to how E2E tests are handled for
Windows runs in Kubernetes.

Some of the tests are Skipped, as they do not pass yet on Windows.

Windows does not collect inodes used stats, thus, the tests that were expecting non-zero
inodes stats were failing.

Signed-off-by: Claudiu Belu <cbelu@cloudbasesolutions.com>

integration/restart_test.go

@@ -1,5 +1,3 @@
-// +build linux
-
 /*
    Copyright The containerd Authors.
 
@@ -19,6 +17,7 @@
 package integration
 
 import (
+	goruntime "runtime"
 	"sort"
 	"testing"
 
@@ -33,6 +32,9 @@ import (
 // Restart test must run sequentially.
 
 func TestContainerdRestart(t *testing.T) {
+	if goruntime.GOOS == "windows" {
+		t.Skip("Skipped on Windows.")
+	}
 	type container struct {
 		name  string
 		id    string
@@ -100,6 +102,9 @@ func TestContainerdRestart(t *testing.T) {
 			runtimeService.StopPodSandbox(sid)
 			runtimeService.RemovePodSandbox(sid)
 		}()
+
+		EnsureImageExists(t, pauseImage)
+
 		s.id = sid
 		for j := range s.containers {
 			c := &s.containers[j]