allows multiple '--cmake_extra_defines' flags (#10953)
allows multiple '--cmake_extra_defines' flags (#10953)

* allows multiple '--cmake_extra_defines' flags

* fix flake8 error
microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime