[SPARK-11761] Prevent the call to StreamingContext#stop() in the listener bus's thread

See discussion toward the tail of https://github.com/apache/spark/pull/9723
From zsxwing :
```
The user should not call stop or other long-time work in a listener since it will block the listener thread, and prevent from stopping SparkContext/StreamingContext.

I cannot see an approach since we need to stop the listener bus's thread before stopping SparkContext/StreamingContext totally.
```
Proposed solution is to prevent the call to StreamingContext#stop() in the listener bus's thread.

Author: tedyu <yuzhihong@gmail.com>

Closes #9741 from tedyu/master.