[HIPIFY] Initial cuDNN support

- based on https://github.com/ROCmSoftwarePlatform/hipDNN.
- lit testing was supplemented with CUDA_DNN_ROOT_DIR for cuDNN testing.
- single cuDNN test was added.


[ROCm/hip commit: fe421c89b2]

projects/hip/hipify-clang/src/Statistics.cpp

@@ -14,7 +14,7 @@ const char *counterNames[NUM_CONV_TYPES] = {
 };
 
 const char *apiNames[NUM_API_TYPES] = {
-    "CUDA Driver API", "CUDA RT API", "CUBLAS API", "CURAND API"
+    "CUDA Driver API", "CUDA RT API", "CUBLAS API", "CURAND API", "CUDNN API"
 };
 
 namespace {