bpo-31861: Add aiter and anext to builtins (#23847)

Co-authored-by: jab <jab@users.noreply.github.com>
Co-authored-by: Daniel Pope <mauve@mauveweb.co.uk>
Co-authored-by: Justin Wang <justin39@gmail.com>
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 706fcbe..72feaed 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -3860,6 +3860,9 @@ def test_builtins_have_signatures(self):
         needs_groups = {"range", "slice", "dir", "getattr",
                         "next", "iter", "vars"}
         no_signature |= needs_groups
+        # These have unrepresentable parameter default values of NULL
+        needs_null = {"anext"}
+        no_signature |= needs_null
         # These need PEP 457 groups or a signature change to accept None
         needs_semantic_update = {"round"}
         no_signature |= needs_semantic_update