Fix GPUTreeLearner crash when there is zero feature
Fix GPUTreeLearner crash when there is zero feature

huanzhang12/lightgbm-gpu,huanzhang12/lightgbm-gpu,huanzhang12/LightGBM,huanzhang12/LightGBM,huanzhang12/lightgbm-gpu,huanzhang12/lightgbm-gpu,huanzhang12/LightGBM,huanzhang12/LightGBM,huanzhang12/lightgbm-gpu,huanzhang12/LightGBM