[Ops] [Optim] Update to 1.9.1.

[wangshangsam]

Ops:

• [x] batchnorm.py
• [x] conv.py
• [x] dropout2d.py
• [x] embedding.py
• [x] layernorm.py
• [x] linear.py
• [ ] [no change needed?] multiheadattention.py
• [x] pool.py
• [ ] transformerencoderlayer.py

Optim:

• [x] adadelta.py
• [x] adam.py
• [ ] lr_scheduler.py