add benchmark_xgboost.py
add benchmark_xgboost.py

ktaneishi/deepchem,miaecle/deepchem,Agent007/deepchem,lilleswing/deepchem,deepchem/deepchem,miaecle/deepchem,ktaneishi/deepchem,miaecle/deepchem,deepchem/deepchem,lilleswing/deepchem,ktaneishi/deepchem,peastman/deepchem,rbharath/deepchem,joegomes/deepchem,joegomes/deepchem,lilleswing/deepchem,Agent007/deepchem,peastman/deepchem,rbharath/deepchem,Agent007/deepchem