Fix fake tensor kernel nesting (#85920)
If you e.g. printed within a decomp which would call `in_kernel_invocation_manager`, on the exit from the manager it would unilaterally remove meta from the tls / set the tensor to return its real device. We should just restore what the existing state was.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85920
Approved by: https://github.com/ezyang, https://github.com/bdhirsh, https://github.com/huydhn
