fix names of gpu probe tests (#1012)
fix names of gpu probe tests (#1012)

Fix build errors for the GPU tests introduced in #1011.
halfflat/arbor,halfflat/arbor,halfflat/arbor,eth-cscs/nestmc-proto,halfflat/arbor,halfflat/nestmc-proto,halfflat/nestmc-proto,halfflat/nestmc-proto,halfflat/arbor,eth-cscs/nestmc-proto,eth-cscs/nestmc-proto