Check Windows case insensitive app name

On Windows if we run `node-debug app` and real file name is App.js,
we have two identical files in resources tree (app.js and App.js),
but we can't set breakpoints in App.js.
This is very suspicious. The server should always send the canonical version of the main app script URL so that we don't have to deal with that in all places that are sending back urls.