[profiler] provide torch.profiler._utils._init_for_cuda_graphs() as a workaround (#100441)
There are known issues with profiling cuda graphs - particularly, if you create a cuda graph before the first use of the profiler, and then run that cuda graph during profiling.
One workaround is to add `with profile(): pass` before creating the cuda graph that you want to profile later.
For convenience, we provide this function to use the workaround. This also adads a test for this workaround, to ensure that it continues working.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100441
Approved by: https://github.com/Chillee, https://github.com/aaronenyeshi
