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: @hfarahat
Reviewed-by: @robingrosman,@pandoublefeng
Signed-off-by: @robingrosman

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

Signed-off-by: alex-yuyue <yue.yu1@huawei.com>

From: @lixiachen
Reviewed-by: @pandoublefeng,@robingrosman
Signed-off-by: @robingrosman

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

From: @lizhenglong1992
Reviewed-by: 
Signed-off-by:

From: @jonyguo
Reviewed-by: @liucunwei,@heleiwang
Signed-off-by: @liucunwei

Turn off lock only after all data is cached

From: @luoyang42
Reviewed-by: @heleiwang,@liucunwei
Signed-off-by: @liucunwei

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

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

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

From: @luoyang42
Reviewed-by: @liucunwei,@heleiwang
Signed-off-by: @liucunwei

Fix error msg of pythontokenizer

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

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

From: @xulei2020
Reviewed-by: 
Signed-off-by:

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

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

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

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