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.
The old versions were renamed to JS_DECLARE_OLD_NATIVE_FUNCTION and
JS_DEFINE_OLD_NATIVE_FUNCTION, and will be eventually removed once all
native functions were converted to the new format.
This is Abstract Operation is required for the majority of
InstantConstructor's and InstantPrototype's methods.
The implementation is not entirely complete, (specifically 2 of the
underlying required abstract operations, ParseTemporalTimeZoneString
and ParseISODateTime are missing the required lexing, and as such are
TODO()-ed) but the majority of it is done.
Here we got our first Temporal object :^)
This patch adds the TimeZone object itself, its constructor and
prototype (currently empty), and a bunch of required abstract operations
