Completed Jobs' Task Status are showing as "Running"

[scarlett2018]

In v0.12.0, we introduced the new Task Status Column for users to indicate status of each tasks used by job.

The problem is: some tasks in the completed (succeeded, failed, stopped) jobs are showing as still running.

[scarlett2018]

@sterowang @fanyangCS @qfyin -

From UX perspective, tasks in Succeed and Failed jobs should not be "Running", we need to fix this.

Per @yqwang-ms - From technical perspective, PS task role are not able to exit by themselves, they are killed on job completion which made launcher always get the latest PS task status as Running.

We need a technical decision about how to fix it. Please suggest.