[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/compare-fastrnn-results.py

@@ -2,6 +2,7 @@ import argparse
 import json
 from collections import namedtuple
 
+
 Result = namedtuple("Result", ["name", "base_time", "diff_time"])