Both at the same time because many of them call construct() in call()
and I'm not keen on adding a bunch of temporary plumbing to turn
exceptions into throw completions.
Also changes the return value of construct() to Object* instead of Value
as it always needs to return an object; allowing an arbitrary Value is a
massive foot gun.
This removes all usages of the non-standard define_property helper
method and replaces all it's usages with the specification required
alternative or with define_direct_property where appropriate.
