When the task with join is paused, the paused workflow cannot be resumed

[houguangqiang]

In the example below, when the workflow is paused by the engine command, and then resume the workflow through the resume api, the workflow status will always be RUNNING.

---
version: '2.0'

name: wb

workflows:
  wf1:
    type: direct

    tasks:
      task1:
        action: std.echo output="Hi!"
        on-complete:
          - task2
          - task3
          - pause

      task2:
        action: std.echo output="Task 2"
        on-success: task4

      task3:
        action: std.echo output="Task 3"
        on-success: task4

      task4:
        action: std.echo output="Task 4"
        join: 2