Check the error of `assertEncoding`.
Confirmed in every place being used.(a place where `getoptions` is used)
assetEncoding: 521767c886/lib/internal/fs.js (L18)
PR-URL: https://github.com/nodejs/node/pull/10913
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
