add axiom filtering property to python bindings (#1061)

This adds a boolean property to kore_axiom_declaration objects which
will be `True` if the axiom is used by the LLVM backend and `False` if
the LLVM backend filters it out.

Author: Dwight Guth

bindings/python/ast.cpp

@@ -178,6 +178,8 @@ void bind_ast(py::module_ &m) {
           py::init(&kore_axiom_declaration::create),
           py::arg("is_claim") = false)
       .def_property_readonly("is_claim", &kore_axiom_declaration::is_claim)
+      .def_property_readonly(
+          "is_required", &kore_axiom_declaration::is_required)
       .def("add_pattern", &kore_axiom_declaration::add_pattern)
       .def_property_readonly("pattern", &kore_axiom_declaration::get_pattern)
       .def_property_readonly("requires", &kore_axiom_declaration::get_requires);