Thread generator through trunc_normal_ (#100810)
This will solve @albertz's issue as described in #98200 , threading the generator argument through the trunc_normal_ function. I'm still working on #99796 (and won't let it stall out), but this fix doesn't trigger any JIT issues, so I think it might be helpful to get it merged now.
Would be happy to iterate on this if there are any issues.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100810
Approved by: https://github.com/Skylion007, https://github.com/albanD
