[BE][Easy][3/19] enforce style for empty lines in import segments in benchmarks/ (#129754)

See https://github.com/pytorch/pytorch/pull/129751#issue-2380881501. Most changes are auto-generated by linter.

You can review these PRs via:

```bash
git diff --ignore-all-space --ignore-blank-lines HEAD~1
```

Pull Request resolved: https://github.com/pytorch/pytorch/pull/129754
Approved by: https://github.com/ezyang

benchmarks/inference/process_metrics.py

@@ -10,6 +10,7 @@ import os
 
 import pandas as pd
 
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Parse output files")
     parser.add_argument("--csv", type=str, help="Path to csv file")

benchmarks/inference/server.py

@@ -1,5 +1,4 @@
 import argparse
-
 import asyncio
 import os.path
 import subprocess