Change to Readdirnames for some cases

There was a couple uses of Readdir/ReadDir here where the only thing the return
value was used for was the Name of the entry. This is exactly what Readdirnames
returns, so we can avoid the overhead of making/returning a bunch of interfaces
and calling lstat everytime in the case of Readdir(-1).

https://cs.opensource.google/go/go/+/refs/tags/go1.20.4:src/os/dir_unix.go;l=114-137

Signed-off-by: Danny Canter <danny@dcantah.dev>

pkg/cri/opts/container.go

@@ -121,7 +121,13 @@ func WithVolumes(volumeMounts map[string]string) containerd.NewContainerOpts {
 // copyExistingContents copies from the source to the destination and
 // ensures the ownership is appropriately set.
 func copyExistingContents(source, destination string) error {
-	dstList, err := os.ReadDir(destination)
+	f, err := os.Open(destination)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	dstList, err := f.Readdirnames(-1)
 	if err != nil {
 		return err
 	}