tests/sixtracklib/opencl: enable test_particles_opencl_c99 unit-test automatically as part of the testsets
tests/sixtracklib/opencl: enable test_particles_opencl_c99 unit-test automatically as part of the testsets

SixTrack/SixTrackLib,SixTrack/SixTrackLib,SixTrack/SixTrackLib,SixTrack/SixTrackLib