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

sys.modules is the one true source.
diff --git a/Python/importdl.c b/Python/importdl.c
index d8656b9..32fb7e1 100644
--- a/Python/importdl.c
+++ b/Python/importdl.c
@@ -215,7 +215,8 @@
     else
         Py_INCREF(path);
 
-    if (_PyImport_FixupExtensionObject(m, name_unicode, path) < 0)
+    PyObject *modules = PyImport_GetModuleDict();
+    if (_PyImport_FixupExtensionObject(m, name_unicode, path, modules) < 0)
         goto error;
 
     Py_DECREF(name_unicode);