Fix symlink interaction with modulinos

When managing executable scripts with `npm install [-g]` in an ASDF context, then ASDF's symlinks break how the conventional modulion snippet works.

```js
#!/usr/bin/env node

export default function main() {
// ...
}

if (import.meta.url === `file://${process.argv[1]}`) { main(); }
```

https://rosettacode.org/wiki/Modulinos

In many cases, Node.js loads the absolute path in `import.meta.url` but a symlink in `process.argv[1]`.

Node.js is documented as normally resolving symlinks automatically. However, asdf-nodejs doesn't use plain files to manage executables, but symlinks. Somewhere in the guts of the `node` interpreter entrypoint handler is an assumption that the names of the script file to load are always plain files.

That deserves a patch upstream to Node.js in its own right.

However, meanwhile, we have two strategies to get asdf-nodejs integrating better with modulinos.

* Patch Node.js as part of the asdf-nodejs build process, with a code snippet to explicitly follow (optional!) symlinks when loading script names.
* Come up with a more complicated modulino snippet that works in both asdf-nodejs and plain host contexts of Node.js installations. Presumably that works with older version managers as well, like nodenv, nodeenv, nvm, n, etc.