- It provides a unified style to express graph and kernel for user.
- It provides a unified IR to represent graph and kernel for developer.
- It breaks the boundary between graph and kernel.
- It provides more opportunities to do compile optimization.

support tensor slice using constexpr

remove tensorslice metagraph

add pynative testcases

support tensor set value by tensor index

use unpack graph primitive instead

add testcases for all grad interface

remove debug log

format code

remove dumpfuncgraph

resolve clang-format

resolve reviews

resolve cpplint

fix review

Signed-off-by: leonwanghui <leon.wanghui@huawei.com>