"SparkListenerSuite.onTaskGettingResult() called when result fetched remotely" test is very slow

The SparkListenerSuite "onTaskGettingResult() called when result fetched remotely" test seems to take between 1 to 4 minutes to run in Jenkins, which seems excessively slow; we should see if there's an easy way to speed this up:

https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/Spark-1.5-Maven-pre-YARN/938/HADOOP_VERSION=1.2.1,label=spark-test/testReport/org.apache.spark.scheduler/SparkListenerSuite/onTaskGettingResult___called_when_result_fetched_remotely/history/