unittests: Fixes TestReplaceFile for Windows

Currently, the test TestReplaceFile/neither_parent_nor_file_exists fails
because the error encountered doesn't match the expected error.

On Windows, if a file is missing, the encountered error is:

The system cannot find the file specified.

And if a folder / parent folder is missing, this error is encoutered instead:

The system cannot find the path specified.

pkg/kubelet/kubeletconfig/util/files/files_test.go

@@ -313,7 +313,7 @@ func TestReplaceFile(t *testing.T) {
 				return nil
 			},
 			desc: "neither parent nor file exists",
-			err:  missingFileError,
+			err:  missingFolderError,
 		},
 	}
 	for _, c := range cases {