Add TorchVitals for DataLoader (#60959)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60959
Add TorchVitals for Dataloader, this indicates that the data loader was enabled.
This is a no-op if TORCH_VITALS environment variable is not set.
Test Plan: buck test mode/dbg caffe2/test:torch -- --regex vitals
Reviewed By: VitalyFedyunin
Differential Revision: D29445146
fbshipit-source-id: d5778fff3dafb3c0463fec7a498bff4905597518
