Issue #20411: Use readline.get_current_history_length to check for the presence…

Issue #20411: Use readline.get_current_history_length to check for the presence of a history, rather than get_history_item, which assumes a history is present.

Lib/site.py

@@ -409,7 +409,7 @@ def enablerlcompleter():
             # want to ignore the exception.
             pass
 
-        if readline.get_history_item(1) is None:
+        if readline.get_current_history_length() == 0:
             # If no history was loaded, default to .python_history.
             # The guard is necessary to avoid doubling history size at
             # each interpreter exit when readline was already configured