bpo-28411: Remove "modules" field from Py_InterpreterState. (#1638)

sys.modules is the one true source.
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 5e1f1d3..c363cfe 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2685,7 +2685,7 @@
         PyType_Ready(&PyZip_Type) < 0)
         return NULL;
 
-    mod = PyModule_Create(&builtinsmodule);
+    mod = _PyModule_CreateInitialized(&builtinsmodule, PYTHON_API_VERSION);
     if (mod == NULL)
         return NULL;
     dict = PyModule_GetDict(mod);