## What changes were proposed in this pull request? SPARK-22713 uses [`eventually` with the default timeout `150ms`](https://github.com/apache/spark/pull/21369/files#diff-5bbb6a931b7e4d6a31e4938f51935682R462). It causes flakiness because it's executed once when GC is slow. ```scala eventually { System.gc() ... } ``` **Failures** ```scala org.scalatest.exceptions.TestFailedDueToTimeoutException: The code passed to eventually never returned normally. Attempted 1 times over 501.22261 milliseconds. Last failure message: tmpIsNull was false. ``` - master-test-sbt-hadoop-2.7 [4916](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.7/4916) [4907](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.7/4907) [4906](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.7/4906) - spark-master-test-sbt-hadoop-2.6 [4979](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.6/4979) [4974](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.6/4974) [4967](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.6/4967) [4966](https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Test%20(Dashboard)/job/spark-master-test-sbt-hadoop-2.6/4966) ## How was this patch tested? Pass the Jenkins. Closes #22432 from dongjoon-hyun/SPARK-22713. Authored-by: Dongjoon Hyun <dongjoon@apache.org> Signed-off-by: Wenchen Fan <wenchen@databricks.com>
