Allow readdirSync to read inside vfs directories

[FoGsesipod]

readdirSync cannot read inside of vfs folders

reproduceable by running this command in devtools retail omori with demo mod installed: demoissue.zip
{let fs = require('fs'); fs.readdirSync('www/' + "img/system/")}
you will notice the first entry is "folder"

however running this command instead
{let fs = require('fs'); fs.readdirSync('www/' + "img/system/folder/")}
returns a error of a file/directory not existing