ext/spl: Add ArrayObject test with property hooks

[Girgias]

As expected, ArrayObject is cursed.

@Crell maybe you could provide more useful test cases? But in any case ArrayObject just, does not care about property hooks.

[iluuu1994]

That's pretty much what I expected. Essentially, ArrayAccess writes directly to the properties table. If you cast it to an array, or use get_mangled_object_vars(), you'd probably see the dynamic properties created for virtual properties.

[Girgias]

In that case, except if @Crell wants to write more edge cases, I'll merge this when I get back to working on the container RFC to be able to check how ArrayObject behaves after my changes.

[Crell]

If you're going to tag me, you'll need to give me more than 12 hours while I'm asleep to respond. 😛

In any case, I think the only time I've used ArrayObject was in one slide in my talk on why to not use arrays. So, I don't really care what happens here and I'm happy to defer to whatever @iluuu1994 feels is best. Especially if your goal is to destroy ArrayObject eventually anyway.