Add support for building the native plugins by CircleCI

[stakemura]

Hi, I'm ready to send PR to build the native plugins by CircleCI.
As the following result showed, CircleCI can build the all (macOS, Windows, Linux, iOS, Android) TFLite 2.10.0 native plugins successfully on free account.

https://app.circleci.com/pipelines/github/stakemura/tf-lite-unity-sample/53/workflows/9995ca29-237f-4276-ad68-2dacd6152387

As for the gpu-api-delegate, please comment out the following patch.

# For gpu-api-delegate branch
# sed -i -e 's/libtensorflowlite_gpu_delegate.so/libtensorflowlite_gpu_api_delegate.so/' ../tensorflow/tensorflow/lite/delegates/gpu/BUILD 
# sed -i -e 's/\":delegate\"/\"\/\/tensorflow\/lite\/delegates\/gpu\/cl:gpu_api_delegate\"/' ../tensorflow/tensorflow/lite/delegates/gpu/BUILD

Also I need some modifications about build_tflite.py to support continuous builds.
For example, I made it possible to return the error code when bazel failed to build.

    ret = subprocess.call(args, cwd=TENSORFLOW_PATH, shell=is_shell)
    if ret != 0:
        sys.exit(ret)

I would appreciate it if you could consider the merge.

[asus4]

@stakemura Thank you for the great PR. Code changes look ok to me. Let me merge it and see it on my CircleCI.