Tweak intra-group parallelism workgroup sizing.
Tweak intra-group parallelism workgroup sizing.

HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark,diku-dk/futhark,HIPERFIT/futhark,diku-dk/futhark