Ruby: &[SPACE][identifier] syntax breaks Ruby parsing

CodeQL's Ruby breaks parsing breaks for the following code:

```ruby
sorted_array = array.sort(& custom_sorts[params[:sortby]])
```

I understand that the following *should* be how this is written, but sometimes people put weird syntax in and it shouldn't break a whole file being parsed:

```ruby
sorted_array = array.sort(&custom_sorts[params[:sortby]])
```

Start by reproducing the Ruby parser failure with the two sort examples in the issue, focusing on the space between `&` and the identifier. Trace the parser entry point that handles this syntax and verify that both forms are accepted without preventing the rest of the file from being parsed.

Scritto dal modello di indicizzazione a partire dal testo della issue.