Test GH Superchips via unified memory

[sbryngelson]

Rogues Gallery has GH superchip nodes available (u-wing?). I have already seen that MFC compiles and runs on these nodes, but it only does so on the GPU part of the chip. To work in 'superchip' mode, one must add a unified memory flag to the CMakeLists for nvhpc, which will let it use the global memory on the CPU part. This should be straightforward.

A relevant Google search: https://www.google.com/search?q=unified+memory+grace+hopper+superchip+flag+nvfortran

Tackling this issue requires access to the Rogues Gallery.