Separating the Tridiagonal Test Case build from the rest of the test so we won't need to build whole x3d2.
FC=mpif90 cmake -B build . -DWITH_2DECOMPFFT=OFF
cmake --build build --target test_cuda_tridiag_cuda_4 # CUDA
cmake --build build --target test_omp_tridiag_omp_4 # OMP
Separating the Tridiagonal Test Case build from the rest of the test so we won't need to build whole x3d2.