Backport check_log updates from master to 21.1

Same as !29032 (merged) but for the 21.1 branch.

This is a backport of all check_log updates from master, particularly the move from a perl script to a python script in !27839 (merged) and various pattern updates like !25808 (merged).

The changes to check_log.pl/.py were simply done by:

git checkout upstream/master -- Trigger/TrigValidation/TrigValTools/bin/check_log.pl Trigger/TrigValidation/TrigValTools/bin/check_log.py

so this is not new code, just a sweep.