Download hadoop-2.8.4.tar.gz during release building or third-parties image building for unit tests

[empiredan]

hadoop-2.8.4.tar.gz failed to be downloaded very frequently for workflows as follows:

The reason could be that during a short period of time there are several tens of test cases started, all of which request hadoop-2.8.4.tar.gz from remote repository. This might trigger throttling for the downloads.

To solve this problem, hadoop-2.8.4.tar.gz can be downloaded during:

• release building: once third-parties have changed, it should be rebuilt and image would not be used, thus download hadoop-2.8.4.tar.gz; or otherwise
• third-parties image building: none of third-parties has ever changed, image would be used, thus third-parties image should include hadoop-2.8.4.tar.gz

Thus there will be 2 pull requests for both conditions:

• build(images): download hadoop-2.8.4.tar.gz during third-parties image building for unit tests #1167
• ci: download hadoop-2.8.4.tar.gz during release building for unit tests once third-parties have changed #1168