[CUDA, tet-suite] enable testing with C++17 and C++20

[tra]

Summary

Also disable the tests for 3-argument hypot() provided by the standard library
since c++17 as CUDA does not provide it.

External/CUDA/CMakeLists.txt

function(create_cuda_test_variant Std VariantSuffix)
   list(APPEND LDFLAGS ${_Cuda_LDFLAGS} ${_Std_LDFLAGS} ${_Stdlib_LDFLAGS})
 
   # Create a separate test target for simple tests that can be built/tested quickly.
   add_custom_target(cuda-tests-simple-${VariantSuffix}
     COMMENT "Build Simple CUDA tests for ${VariantSuffix}")
   create_local_cuda_tests(${VariantSuffix})
   add_dependencies(cuda-tests-simple cuda-tests-simple-${VariantSuffix})
 
-  if(DEFINED THRUST_PATH AND (NOT ${Std} STREQUAL "c++14"))
+  if(DEFINED THRUST_PATH AND (NOT ${Std} IN_LIST "c++14;c++17;c++20"))
     create_thrust_tests(${VariantSuffix})
   endif()
 
   # Target for CUDA tests that take little time to build and run.
   add_custom_target(check-cuda-simple-${VariantSuffix}
     COMMAND ${TEST_SUITE_LIT} ${TEST_SUITE_LIT_FLAGS}
             ${CUDA_SIMPLE_TEST_TARGETS}
     WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
if (_CudaArchList)
       message(STATUS "Building ${_Cuda_Suffix} targets for ${_CudaArchList}")
     else()
       message(WARNING "${_Cuda_Suffix} does not support ${CUDA_GPU_ARCH} GPUs. Skipped.")
       continue()
     endif()
     list(APPEND _Cuda_CPPFLAGS ${_CudaArchFlags})
 
     set(_Cuda_Libs cudart-${_CudaVersion})
-    foreach(_Std IN ITEMS "c++98" "c++11" "c++14")
+    foreach(_Std IN ITEMS "c++98" "c++11" "c++14" "c++17" "c++20")
       set(_Std_Suffix "${_Std}")
       set(_Std_CPPFLAGS -std=${_Std})
       set(_Std_LDFLAGS -std=${_Std})
       foreach(_GccPath IN LISTS GCC_PATHS)
         get_version(_GccVersion ${_GccPath})
         set(_Gcc_Suffix "libstdc++-${_GccVersion}")
         # Tell clang to use libstdc++ and where to find it.
         set(_Stdlib_CPPFLAGS -stdlib=libstdc++ -gcc-toolchain ${_GccPath})

External/CUDA/cmath.cu

__device__ void test_hypot()
     assert(std::hypot(3., 4) == 5);
     assert(std::hypot(3., 4.) == 5);
     assert(std::hypot(3., 4.f) == 5);
 
     assert(std::hypot(3.f, 4) == 5);
     assert(std::hypot(3.f, 4.) == 5);
     assert(std::hypot(3.f, 4.f) == 5);
 
-#if __cplusplus >= 201703L && STDLIB_VERSION >= 2017
+    // CUDA does not provide 3-argument hypot().
+#if 0 // __cplusplus >= 201703L && STDLIB_VERSION >= 2017
     static_assert((std::is_same<decltype(std::hypot((float)0, (float)0, (float)0)), float>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (bool)0, (float)0)), double>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (unsigned short)0, (double)0)), double>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (unsigned int)0)), double>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (double)0, (long)0)), double>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (int)0, (long long)0)), double>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (int)0, (unsigned long long)0)), double>::value), "");
     static_assert((std::is_same<decltype(std::hypot((float)0, (double)0, (double)0)), double>::value), "");