ATR-23441: Fixing unit tests in TrigOutputHandling
This will allow enabling one of the two unit tests of TrigOutputHandling, which were disabled after migration to LCG100. The fix by @mnowak is described in https://its.cern.ch/jira/browse/ATR-23441
Tagging @tbold to take a look and comment/approve.
EDIT: added a fix of the second unit test. It required setting a StreamTag to HLTResultMT object.
Edited by Oleg Kuprash