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 one is a bit unusual, so to clarify:
Previously, callers of get_iterator_values() would supply a callback
that would return an IterationDecision, and an enum to indicate whether
iterator_close() should be invoked upon IterationDecision::Break.
Now, use of both those enums is removed, and callers must return an
Optional<Completion>. If a Completion is provided, the iterator will be
closed, and that completion will be returned from get_iterator_values.
Otherwise, once the iterator is exhausted, a default-initialized
Completion will be returned.
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.
This makes the implicit run-time assertion in PropertyName::to_string()
into an explicit compile-time requirement, removes a wasteful FlyString
-> PropertyName -> FlyString construction from NativeFunction::create()
and allows setting the function name to a null string for anonymous
native functions.
