Fix incorrect simulation flag in RICH test samples

FYI @sponce The sample you recently added had simulation incorrectly set to True for some real data MDF samples.

python/MooreTests/line-and-stream-rates.py

@@ -21,6 +21,7 @@ from Moore.streams import (bank_types_for_detectors,
 import json
 import argparse
 import csv
+import os
 from pprint import pprint
 from dataclasses import dataclass, field
 from typing import List, Dict
@@ -373,7 +374,7 @@ if __name__ == '__main__':
     options.input_type = args.file_type
     options.input_stream = args.stream
     options.evt_max = -1  # Always want to run over all events in this script
-    options.ioalg_buffer_nb_events = 200  # to be able to cope with large events
+    options.ioalg_buffer_nb_events = os.environ['IOALG_BUFFER_EVENTS']
     options.gaudipython_mode = True
     config = configure_input(options)