Clean up leftover processes on non-ephemeral Windows runner (#93414)
In some rare cases, checking out PyTorch on non-ephemeral Windows G5 runner could fail because of leftover processes from the previous workflow. For example, https://github.com/pytorch/pytorch/actions/runs/4058503816/jobs/6986773162
Pull Request resolved: https://github.com/pytorch/pytorch/pull/93414
Approved by: https://github.com/clee2000
