Move pkg/testutil to internal/testutil

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/testutil/helpers_windows.go

@@ -1,27 +0,0 @@
-/*
-   Copyright The containerd Authors.
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-*/
-
-package testutil
-
-import "testing"
-
-// RequiresRoot does nothing on Windows
-func RequiresRoot(t testing.TB) {
-}
-
-// RequiresRootM is similar to RequiresRoot but intended to be called from *testing.M.
-func RequiresRootM() {
-}