Draft: ISF_ValidationMT: Switched MP validation tests to use multiple IOVs and Round Robin

MP validation tests which compare CA-based and legacy config outputs were switched to the round robing mode in order to ensure consistent distribution of events to MP workers in two simulation jobs.

This is an alternative way to address MP validation test failures discussed in ATLASSIM-6372. Another solution (to switch these jobs to use single IOVs) was implemented in !61881 (merged)