---
Remove the routine of handling isolated nodes in Renormalize.
Add isolated nodes from Parser&Resolver.
Modify isolated nodes handling in FG&Manager.
Optimize the renormalize routines.
Other optimizations.

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: @zichun_ye
Reviewed-by: @wang_zi_dong,@sunnybeike
Signed-off-by:

fix typo in probability module

fix pylint in msp

From: @zyx5256
Reviewed-by: @liangchenghui,@kingxian
Signed-off-by: @liangchenghui

From: @dangjiaqi1
Reviewed-by: 
Signed-off-by:

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

From: @shallydeng
Reviewed-by: @zichun_ye,@sunnybeike
Signed-off-by:

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

Merge pull request !7581 from lilei/modify_bug

Merge pull request !6760 from lijiaqi/sparse_optimizer

Merge pull request !7361 from YuJianfeng/master

Merge pull request !7339 from qujianwei/master

Merge pull request !7144 from chenzhongming/zomi_master