Examine clang-15 failure on CUDA Gradient script

[kchristin22]

The test of GradientCuda.cu was indicated as expected to fail with clang-15. The changes applied to this script in #806 will probably not have any effect on that, so the problem remains. During development though it was shown that errors where produced when CUDA Toolkit and Clang versions were incompatible.

TODO:

• Install a CUDA version that is old enough for clang-15 and is fully supported by your system
• Compile GradientCuda.cu with -fdump-derived-fn option --> expected result: the gradient function is printed on the terminal
• Validate the run-time results