[SPARK-28418][PYTHON][SQL] Wait for event process in 'test_query_execution_listener_on_collect'

It fixes a flaky test:

```
ERROR [0.164s]: test_query_execution_listener_on_collect (pyspark.sql.tests.test_dataframe.QueryExecutionListenerTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jenkins/python/pyspark/sql/tests/test_dataframe.py", line 758, in test_query_execution_listener_on_collect
    "The callback from the query execution listener should be called after 'collect'")
AssertionError: The callback from the query execution listener should be called after 'collect'
```

Seems it can be failed because the event was somehow delayed but checked first.

Manually.

Closes apache#25177 from HyukjinKwon/SPARK-28418.

Authored-by: HyukjinKwon <[email protected]>
Signed-off-by: HyukjinKwon <[email protected]>
(cherry picked from commit 66179fa)
Signed-off-by: HyukjinKwon <[email protected]>

Author: HyukjinKwon

python/pyspark/sql/tests.py

@@ -3707,6 +3707,7 @@ def test_query_execution_listener_on_collect(self):
             self.spark._jvm.OnSuccessCall.isCalled(),
             "The callback from the query execution listener should not be called before 'collect'")
         self.spark.sql("SELECT * FROM range(1)").collect()
+        self.spark.sparkContext._jsc.sc().listenerBus().waitUntilEmpty(10000)
         self.assertTrue(
             self.spark._jvm.OnSuccessCall.isCalled(),
             "The callback from the query execution listener should be called after 'collect'")
@@ -3721,6 +3722,7 @@ def test_query_execution_listener_on_collect_with_arrow(self):
                 "The callback from the query execution listener should not be "
                 "called before 'toPandas'")
             self.spark.sql("SELECT * FROM range(1)").toPandas()
+            self.spark.sparkContext._jsc.sc().listenerBus().waitUntilEmpty(10000)
             self.assertTrue(
                 self.spark._jvm.OnSuccessCall.isCalled(),
                 "The callback from the query execution listener should be called after 'toPandas'")