From: @yangzhenzhang
Reviewed-by: @kisnwang,@stsuteng
Signed-off-by: @stsuteng

From: @dayschan
Reviewed-by: @gaoxiong1,@dylangeng,@gaoxiong1
Signed-off-by: @dylangeng,@dylangeng

1. set class GraphKernel as deprecated, and treat it as Cell
2. set class InplaceAssign as deprecated, suggested using Assign instead.
3. set op_selector as deprecated, removed the _selected_ops and _selected_grad_ops, replaced with real operations
4. removed the two passes of GraphKernel from frontend
5. removed the GraphKernel's codes from other modules

From: @lichen666
Reviewed-by: @kisnwang,@zhunaipan
Signed-off-by: @zhunaipan

From: @liujunzhu
Reviewed-by: @zhoufeng54,@guoqi1024
Signed-off-by: @guoqi1024

From: @jojobugfree
Reviewed-by: 
Signed-off-by:

The basic idea is: exploits data dependency to control the execution order
of side-effect operations, and keep the semantics of ANF unchanged.

The ControlDepend primitive is removed and there are two primitives added:

1. UpdateState:
```
  a = Assign(para, value)
```
became:
```
  a = Assign(para, value, u)
  u = UpdateState(u, a)
```

2. Load:
```
  x = Add(para, value)
```
became:
```
  p = Load(para, u)
  x = Add(p, value)
  u = UpdateState(u, p)
```

From: @jinyaohui
Reviewed-by: 
Signed-off-by:

From: @gong_zi_yan
Reviewed-by: @stsuteng,@zhunaipan
Signed-off-by: @stsuteng

From: @gong_zi_yan
Reviewed-by: 
Signed-off-by:

From: @huangxinjing
Reviewed-by: @zhunaipan,@stsuteng
Signed-off-by: @stsuteng

Fix input check

From: @gong_zi_yan
Reviewed-by: @caozhou_huawei,@yao_yf,@stsuteng,@zh_qh
Signed-off-by: @stsuteng