do* works differently in top-level functions vs in methods

[bbrk24]

At the top level:

->
  do*
   yield foo
   yield bar
// vvv
function () {
  return (function* () {
    {
      yield foo;
      yield bar;
    }
  })();
}

In a method:

{
  f()
    do*
     yield foo
     yield bar
}
// vvv
{
  *f() {
    (function* () {
      {
        yield foo;
        yield bar;
      }
    })();
  }
}

I think the latter is a bug, since it never returns or yields anything.

[edemaine]

The latter example is also missing a return, but probably because returns aren't implicit in generators.

This bug also causes getters to fail to transpile with error "Getters and setters cannot be generators":

{
  get f()
    do*
      yield foo
      yield bar
}

So we might add this to tests once fixed.