add shell scripts to run training on single node and multiple nodes. (#424)

* add shells, test=develop

tools/benchmark/run_multi_nodes.sh

+#!/usr/bin/env bash
+
+# IP Addresses of all nodes, modify it corresponding to your own environment
+ALL_NODE_IPS="10.10.10.1,10.10.10.2"
+# IP Address of the current node, modify it corresponding to your own environment
+CUR_NODE_IPS="10.10.10.1"
+
+python -m paddle.distributed.launch \
+    --cluster_node_ips=$ALL_NODE_IPS \
+    --node_ip=$CUR_NODE_IPS \
+    --gpus="0,1,2,3" \
+    tools/train.py \
+        -c ./configs/ResNet/ResNet50.yaml \
+        -o print_interval=10

tools/benchmark/run_single_node.sh

+#!/usr/bin/env bash
+
+python -m paddle.distributed.launch \
+    --gpus="0,1,2,3" \
+    tools/train.py \
+        -c ./configs/ResNet/ResNet50.yaml \
+        -o print_interval=10