[Libomptarget] Do not pass 'nogpulib' to the non-LTO Nvidia tests (#70327)

Summary:
For the other tests we pass `-nogpulib` to ensure that we set up the
needed libraries correctly. However, this caused problems for the
non-LTO build and test of Nvidia systems. In general this is because we
would do a separate compile of the libomptarget device runtime and then
link in that cubin. This exercised the runtime in a lot of ways it's not
used to, since doing things this way was hardly expected or tested. This
patch disables it only for the Nvidia non-LTO build so that we still get
the effect of `--liboimptarget-nvptx-bc-path` rather than ignoring it.