[profiler] Global function for controlling fwd-bwd connection behavior (#102492)
Summary: In https://github.com/pytorch/pytorch/pull/102424, we'll re-introduce forward-backward links. We assume that most users will want to see them, but in case there are issues, we'll provide these APIs for turning them on and off.
Differential Revision: D46266365
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102492
Approved by: https://github.com/aaronenyeshi
