* test: add unit tests for graph_opt_backend
* refactor(tests): improve graph optimization test structure and readability
* fix(tests): correct CUDA graph related typos in test files
- Fix class name: TestCUDAGrpahSubgraph -> TestCUDAGraphSubgraph
* refactor(test): support attention layer and optimize graph optimization backend test to eliminate redundant baseline calculations
* remove some func call
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Co-authored-by: RAM <gstian5555@outlook.com>
Co-authored-by: Tao Luo <luotao02@baidu.com>