From: @zhangbuxue
Reviewed-by: @ginfung
Signed-off-by:

---
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.

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

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

From: @Somnus2020
Reviewed-by: 
Signed-off-by:

From: @yanglf1121
Reviewed-by: 
Signed-off-by:

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

From: @liangzhibo
Reviewed-by: @zh_qh,@chenfei52
Signed-off-by: @zh_qh

From: @liangzhibo
Reviewed-by: @zh_qh,@chenfei52
Signed-off-by: @zh_qh

From: @liangzhibo
Reviewed-by: @chenfei52
Signed-off-by:

Merge pull request !7838 from LiangZhibo/master