- add more logging for better fault tracking
- generalize for use in either RELEASE or DEBUG build mode (default to 'release')
- improve variable naming precision/specificity
- consolidate configuration
- DRY improvements
- improve flexibility/robustness in the face of missing reference test info
- add reference test info IDs and additional logging to help diagnose testing failures
- includes parallel refactor of 'util/run-gnu-test.sh'