Created by: baojun-nervana

This PR is enable ngraph pass for parallel executor through build strategy.

• ngraph_subgraph_pass will be enabled through build strategy when FLAGS_use_ngraph=true
• ngraph_subgraph_pass is updated to handle training. The pass uses subgraph_detector.cc. The subgraph_detector.cc was developed for inference and need a workaround for training.

This PR has a dependency on PR #19155 CC: @LeoZhao-Intel @pawelpiotrowicz