[HIPIFY] Introduce CUDA installation path option '-cuda-path'

Repeats clang's '--cuda-path' option.

[Reason]
In case of absence of any other clang's options setting '-cuda-path' allows not to specify separator '--' before clang's '--cuda-path'.

+ Tests and scripts are updated accordingly.

tests/hipify-clang/unit_tests/libraries/cuRAND/poisson_api_example.cu

@@ -1,4 +1,4 @@
-// RUN: %run_test hipify "%s" "%t" %cuda_args
+// RUN: %run_test hipify "%s" "%t" %hipify_args %clang_args
 
 // Taken from: http://docs.nvidia.com/cuda/curand/device-api-overview.html#poisson-api-example
 /*