BackupForStateTransferTest.testStateTransferWithClusterIdle random failures

java.lang.AssertionError: 
	at org.infinispan.xsite.statetransfer.BackupForStateTransferTest$6.assertInCache(BackupForStateTransferTest.java:138)
	at org.infinispan.xsite.AbstractXSiteTest.assertInSite(AbstractXSiteTest.java:178)
	at org.infinispan.xsite.statetransfer.BackupForStateTransferTest.assertNoStateTransferInReceivingSite(BackupForStateTransferTest.java:133)
	at org.infinispan.xsite.statetransfer.BackupForStateTransferTest.testStateTransferWithClusterIdle(BackupForStateTransferTest.java:94)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
... Removed 20 stack frames