Model the `IndexType` as `uint64_t` when converting to a python integer. With the python bindings, ```python DenseIntElementsAttr(op.attributes["attr"]) ``` used to `assert` when `attr` had `index` type like `dense<[1, 2, 3, 4]> : vector<4xindex>`. --------- Co-authored-by: Christopher McGirr <christopher.mcgirr@amd.com> Co-authored-by: Tiago Trevisan Jost <tiago.trevisanjost@amd.com>