Improve test suite for better maintainability

This improves code organization for the test suite while preserving all
existing functionality.
- Add reusable test runner functions, such as run_expr_tests
- Consolidate repetitive test patterns into data arrays
- Create unified error reporting through report_test_failure()
- Suppress compiler error output and "Aborted (core dumped)" messages
- Add progress indicators and colored output support
- Improve test categorization and summary reporting

Author: jserv