[SPARK-12021][STREAMING][TESTS] Fix the potential dead-lock in StreamingListenerSuite

In StreamingListenerSuite."don't call ssc.stop in listener", after the main thread calls `ssc.stop()`,  `StreamingContextStoppingCollector` may call  `ssc.stop()` in the listener bus thread, which is a dead-lock. This PR updated `StreamingContextStoppingCollector` to only call `ssc.stop()` in the first batch to avoid the dead-lock.

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #10011 from zsxwing/fix-test-deadlock.