Automatically add types to Python modules

PR python/32163 points out that various types provided by gdb are not
added to the gdb module, so they aren't available for interactive
inspection.  I think this is just an oversight.

This patch fixes the problem by introducing a new helper function that
both readies the type and then adds it to the appropriate module.  The
patch also poisons PyType_Ready, the idea being to avoid this bug in
the future.

v2:
* Fixed a bug in original patch in gdb.Architecture registration
* Added regression test for the types mentioned in the bug

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32163
Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>

gdb/python/py-cmd.c

@@ -557,7 +557,7 @@ gdbpy_initialize_commands (void)
   int i;
 
   cmdpy_object_type.tp_new = PyType_GenericNew;
-  if (PyType_Ready (&cmdpy_object_type) < 0)
+  if (gdbpy_type_ready (&cmdpy_object_type) < 0)
     return -1;
 
   /* Note: alias and user are special.  */
@@ -587,10 +587,6 @@ gdbpy_initialize_commands (void)
 	return -1;
     }
 
-  if (gdb_pymodule_addobject (gdb_module, "Command",
-			      (PyObject *) &cmdpy_object_type) < 0)
-    return -1;
-
   invoke_cst = PyUnicode_FromString ("invoke");
   if (invoke_cst == NULL)
     return -1;