Creating syntax objects without a context now fails when pushed through the parser

Created by: natefaubion

I believe its tied to https://github.com/mozilla/sweet.js/commit/7888722d0c5225bbf8324716083561cfac27b3f3

macro fun {
  case { _ } => {
     return [
       makeKeyword('function'),
       makeDelim('()', []),
       makeDelim('{}', [])
     ];
   }
 }

var f = fun;

The range ends up being undefined which fails in wrapTrackingFunction.