【cherry-pick 1.8】fix ports conflict when use paddlecloud to launch analogue multi-nodes#27117

Merged

danleifeng merged 5 commits intoPaddlePaddle:release/1.8from danleifeng:launch_port_1.8

Sep 15, 2020

+59-33

Commits on Sep 7, 2020

add DISTRIBUTED_TRAINER_ENDPOINTS env for cloud;test=develop
danleifeng
committed

Commits on Sep 8, 2020

Commits on Sep 10, 2020