This enables an option that was being done unconditionally: to swap the `if` and `else` branches if the condition is shorter when negated.
Enabled by default.
This test suite has been in use for a long time now, in place of the obsolete and unmanageable testparser.py and testfuncs.py. It verifies the complete optimizer output to stdout and stderr, to ensure that the output matches the expectations.
See unit_tests/README.txt for more info.