Don't break when the actual type is a certain CF array type that I can't write a test for :(

Found this when working with `AddressBook.framework`, which was returning some kind of `CFArrayRef` that, when cast to `NSArray *` and then used for list comprehension, resulted in stacking out on a recursive call to `objc_release`. The problem was the creation of the result variable in the comprehension implementations, which used `[[[self class] new] mutableCopy]` for portability. This turned out to be fragile for bridged Core Foundation objects (surprise!), and has been removed in favour of an explicit type argument to the implementation macros.

Unfortunately the original implementation works fine with objects created with `CFArrayCreate`, so there is no new test for this :cry: