Fix minor whitespace typo in tools/test_history.py (#54504)
Summary:
oops
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54504
Test Plan:
```
tools/test_history.py --help
```
Reviewed By: walterddr
Differential Revision: D27262271
Pulled By: samestep
fbshipit-source-id: 0f47e9a69d35a605c558f6c86e3e2ca98720ff86
