[Inference]Fused the gate and up proj in mlp，and optimized the autograd process. (#5365)

* fused the gate and up proj in mlp

* fix code styles

* opt auto_grad

* rollback test_inference_engine.py

* modifications based on the review feedback.

* fix bugs in flash attn

* Change reshape to view

* fix test_rmsnorm_triton.py

colossalai/kernel/triton/rms_layernorm.py

@@ -49,7 +49,6 @@ if HAS_TRITON:
             # Write output
             tl.store(Y + cols, y.to(tl.float16), mask=mask)
 
-    @torch.no_grad()
     def rms_layernorm(x, weight, eps, norm_output=None):
         # allocate output
         y = torch.empty_like(x) if norm_output is None else norm_output