Support array and tuple types in AbstractEvaluator/QueryEngine

Right now the abstractevaluator only supports bits types. array and tuple types are basically ignored. It should be expanded to handle these types. Basically the fundamental datatype held for each node needs to be changed from AbstractEvaluator::Vector to a LeafTypeTree. See [xls/data_structures/leaf_type_tree.h](https://github.com/google/xls/blob/main/xls/data_structures/leaf_type_tree.h). A LeafTypeTree is a container which holds an element for each leaf in a XLS type.

One complication is users like z3 which may have their own special array types which we want may to use.