Currently, TypeAry::is_null_free() only return null if the element type is an inline type, checked with is_inlinetypeptr(). However, we could also have a super type that merges two null free arrays - either object or an abstract value type for which is_inlinetypeptr() returns false because it does not have a backing ciInlineKlass.

We should update TypeAry::is_null_free() to consider any null-free array, including autobox caches.