Test failure: org.apache.spark.sql.execution.adaptive.AdaptiveQueryExecSuite.multiple joins

https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/112373/testReport

org.scalatest.exceptions.TestFailedException: 2 did not equal 1

This doesn't look like occurring rarely - it had been passed, but it was failed once, and failed nearly 1 or 2 failure(s) per a page of history.

https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/112373/testReport/junit/org.apache.spark.sql.execution.adaptive/AdaptiveQueryExecSuite/multiple_joins/history

(Please track older iteratively to see how often it failed.)