Let incomplete closure tests pass

TALES path evaluation logic was not enough to pass closure tests.
They can be passed if using this modification.
Something is only an instance of `Closure` if it's actually a closed over function--not all `callable`s are closures. For instance, `['classname', 'methodname']` is callable but not a `Closure`, so wouldn't pass that check. Not sure if that makes a difference in the intent here or not, however.