Update run_classifier.sh

demo/text-classification/run_classifier.sh

 export FLAGS_eager_delete_tensor_gb=0.0
-export CUDA_VISIBLE_DEVICES=1,2,3,4
+export CUDA_VISIBLE_DEVICES=0
 
 # User can select chnsenticorp, nlpcc_dbqa, lcqmc and so on for different task
 DATASET="chnsenticorp"