Proper File Handle Management for StateLogger #1211
This PR ensures proper cleanup of file writers to prevent resource leaks during SQLancer's execution.
Changes:

1. Implement closeWriters() method to handle all FileWriter cleanup
2. Add cleanup in both normal execution and error paths
3. Maintain all existing logging functionality
4. Remove redundant individual writer close calls
   Benefits:
5. Prevents file descriptor leaks in long-running tests
6. Ensures log data is properly flushed
7. More reliable resource management
8. No impact on existing logging behavior
   The changes focus specifically on resource cleanup while keeping all logging functionality identical.

@mrigger