update code modernization and debugging improvements

[ismailtsdln]

Updated deprecated dependencies and enhanced error reporting for better debugging experience and modern Go compatibility.

🔧 Key Changes

Code Modernization

• Deprecated API Migration: Replaced all ioutil functions with modern os and io equivalents across 10 files
• Cleanup: Removed redundant f.Close() calls in cert_util.go for cleaner resource management

Enhanced Error Reporting

• Improved Debugging: Updated sanity check failure messages in test_executor.go to include:
• Test suite name
• Expected result
• Actual result
• Impact: Faster debugging of implementation failures with detailed context

✅ Verification

• Backward Compatibility: All functionality preserved
• Modern Standards: Code now uses current Go best practices
• Better Debugging: Error messages provide actionable information

📈 Impact

• Future-Proofing: Removed deprecated dependencies
• Developer Experience: More informative error messages reduce debugging time
• Code Quality: Cleaner resource management and modern patterns

[JackOfMostTrades]

Looks good to me. Thanks for the contribution!