remove tools/setup_helpers/cudnn.py (#25876)
Summary:
FindCUDNN.cmake and cuda.cmake have done the detection. This commit deletes `tools/setup_helpers/cudnn.py` as it is no longer needed.
Previously in https://github.com/pytorch/pytorch/issues/25482, one test failed because TensorRT detects cuDNN differently, and there may be situations we can find cuDNN but TensorRT cannot. This is fixed by passing our detection result down to TensorRT.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25876
Differential Revision: D17346270
Pulled By: ezyang
fbshipit-source-id: c1e7ad4a1cb20f964fe07a72906f2f002425d894
