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

free

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)
```

Signed-off-by: zjun <zhangjun0@huawei.com>

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

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

From: @lichen666
Reviewed-by: 
Signed-off-by:

Merge pull request !5692 from BowenK/pre_ad

Merge pull request !5488 from zhangbuxue/add_check_tensor_before_compile_graph

Signed-off-by: zhoufeng <zhoufeng54@huawei.com>

Signed-off-by: zhoufeng <zhoufeng54@huawei.com>

Merge pull request !2948 from amongo/FixControlFlow

add join for ref

adjust env eliminate to eliminate all env ops

add partial app cache

resolve while endless

fix env eliminate

support for "for while" cases

fix join shape error