pytorch

148d4926 - [SPMD] Implement split_fused_optimizer to split one fused_optimizer node to two (#98784)

[SPMD] Implement split_fused_optimizer to split one fused_optimizer node to two (#98784) Several optimization passes requires the ability to split the fused_optimizer. This PR adds the API to support the use cases. Differential Revision: [D44806450](https://our.internmc.facebook.com/intern/diff/D44806450/) Pull Request resolved: https://github.com/pytorch/pytorch/pull/98784 Approved by: https://github.com/mrshenli