Function starunpack_helper miss a break statement

[zikcheng]

In function starunpack_helper, code snippet below seems to figure out whether there is a starred argument. I think it's better to insert a break statement below seen_star = 1; to stop the iteration as early as possible.

int seen_star = 0;
for (Py_ssize_t i = 0; i < n; i++) {
    expr_ty elt = asdl_seq_GET(elts, i);
    if (elt->kind == Starred_kind) {
        seen_star = 1;
    }
}

[corona10]

@zikcheng Do you want to submit the patch?