path resolution fails on Windows #249

Compiled scripts produce ERR_MODULE_NOT_FOUND exceptions on all of my Windows machines. This seems to have something to do with the paths generated by the compiler and some unexpected behavior from racket/path.

Racks is able to successfully compile the program, but when I try to run the module with Node, it errors out trying to import a file called 'untimecore.js'. I took a look through the compiled version of my racket code, and found this at the top of the file:

import * as $rjs_core from '..\runtime\core.js';
import * as M0 from "..\runtime\kernel.rkt.js";
import * as M1 from "..\collects\racket\private\modbeg.rkt.js";

These aren't the intended paths, because the single back-slashes escape characters in the file names. This is why '..\runtime\core.js' becomes something like ' untimecore.js'.
I have a working theory for why the paths are being generated this way, although I am new to the codebase, so it could easily be something else.

I suspected this was a windows-specific problem, so I went looking for how these import statements are built. I found that the function simple-module-path in util.rkt can call simple-form-path, which in turn calls simplify-path.

According to the documentation, simplify-path will replace / with \ on Windows, so it certainly seems like this might be the culprit. However, this isn't a bug with simplify-path but the intended behavior. It might be necessary to go through the code and differentiate between when a path is going to be used with the file system and when the path string is to be used in compiled javascript code.