Re-enable CRIU tests by not using overlayfs snapshotter

While the issue hasn't been fixed in the kernel yet, we can workaround
the issue by not using overlayfs snapshotter.

The newly added step runs all tests that match /TestCheckpoint/.
So, TestCRWithImagePath has been renamed to match the regexp.

Fixes #3930.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

integration/client/container_checkpoint_test.go

@@ -414,7 +414,7 @@ func TestCheckpointLeaveRunning(t *testing.T) {
 	<-statusC
 }
 
-func TestCRWithImagePath(t *testing.T) {
+func TestCheckpointRestoreWithImagePath(t *testing.T) {
 	if !supportsCriu {
 		t.Skip("system does not have criu installed")
 	}