Closing the file stream after saving the evaluation data

[FauziAkram]

Closing the file stream after saving the evaluation data to avoid resource leaks.

When we open a file stream (e.g., using std::ofstream), the operating system allocates resources to handle the file. These resources may include file handles, buffers, and other data structures.
If we don't explicitly close the file stream after you're done with it, the file remains open, and its associated resources are not released.

Closing a file stream is a best practice for resource management. It ensures that data is written to the file, and prevents resource exhaustion, data loss, and file-locking issues.

No functional change, bench: 1241996

[Disservin]

That's a bit redudant imo, ofstream should be an RAII object which closes automatically at the end of the scope. Which in this case is 3 lines below.