Issue 516 - JSHydra: return {foo:bar} produces broken code

autotest/abprewrite_source.js

 const Cc = Components.classes
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 const Cr = Components.results;
 const Cl = Components.unknown;
 
 Cu.import("foo/bar.jsm");
 
 let {Timeline} = require("timeline");
 let {Utils} = require("utils");
@@ skipping 23 matching lines @@
 
 for (k of fooList)
   alert(k);
 
 
 let a = function() 1;
 let b = {
   get foo() 1
 };
 
+function foo()
+{
+  return {foo: 1, bar: 2};
+}
+
 if (a == b)
   foo();
 else if (a == c)
   bar();
 else
   bas();
 if (a == b);
 
 for (let a = 0; a < b.length; a++)
   foo();
@@ skipping 14 matching lines @@
     yield i;
   }
 }
 var a = function()
 {
   for (var i = 0; i < 10; i++)
   {
     yield i;
   }
 };