Fix random test failure on TestDummyVirusScanner

java.lang.AssertionError: invoke on features error [Holder [type=class org.nuxeo.ecm.core.test.CoreFeature], Holder [type=class org.nuxeo.ecm.core.test.TransactionalFeature], Holder [type=class org.nuxeo.runtime.test.runner.ContainerFeature], Holder [type=class org.nuxeo.runtime.test.runner.RuntimeFeature], Holder [type=class org.nuxeo.runtime.test.runner.RandomBug$Feature], Holder [type=class org.nuxeo.runtime.test.runner.ConditionalIgnoreRule$Feature], Holder [type=class org.nuxeo.runtime.test.runner.MDCFeature]]
	at org.nuxeo.runtime.test.runner.FeaturesLoader.apply(FeaturesLoader.java:123)
	at org.nuxeo.runtime.test.runner.FeaturesLoader.apply(FeaturesLoader.java:113)
	at org.nuxeo.runtime.test.runner.FeaturesRunner.afterRun(FeaturesRunner.java:167)
	at org.nuxeo.runtime.test.runner.FeaturesRunner$AfterClassStatement.evaluate(FeaturesRunner.java:237)
	at org.nuxeo.runtime.test.runner.FeaturesRunner$RulesFactory$1.evaluate(FeaturesRunner.java:429)
	at org.nuxeo.runtime.test.runner.FeaturesRunner$BeforeClassStatement.evaluate(FeaturesRunner.java:218)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:27)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
	at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.createRequestAndRun(JUnitCoreWrapper.java:113)
	at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.executeEager(JUnitCoreWrapper.java:85)
	at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.execute(JUnitCoreWrapper.java:54)
	at org.apache.maven.surefire.junitcore.JUnitCoreProvider.invoke(JUnitCoreProvider.java:134)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
	Suppressed: java.lang.AssertionError: leaked 2 sessions
		at org.nuxeo.ecm.core.test.CoreFeature.afterRun(CoreFeature.java:240)
		at org.nuxeo.runtime.test.runner.FeaturesRunner.lambda$afterRun$4(FeaturesRunner.java:167)
		at org.nuxeo.runtime.test.runner.FeaturesLoader.apply(FeaturesLoader.java:126)
		... 24 more
		Suppressed: org.nuxeo.ecm.core.api.CoreSessionService$CoreSessionRegistrationInfo: CoreSessionDebugInfo(Nuxeo-Work-default-1:3873888098328720.1284218027, test/system#1521)
			at org.nuxeo.ecm.core.api.CoreSessionServiceImpl.createCoreSession(CoreSessionServiceImpl.java:44)
			at org.nuxeo.ecm.core.api.CoreInstance.openCoreSession(CoreInstance.java:163)
			at org.nuxeo.ecm.core.api.CoreInstance.openCoreSessionSystem(CoreInstance.java:98)
			at org.nuxeo.ecm.core.event.impl.ReconnectedEventBundleImpl.getReconnectedCoreSession(ReconnectedEventBundleImpl.java:93)
			at org.nuxeo.ecm.core.event.impl.ReconnectedEventBundleImpl.getReconnectedEvents(ReconnectedEventBundleImpl.java:111)
			at org.nuxeo.ecm.core.event.impl.ReconnectedEventBundleImpl.iterator(ReconnectedEventBundleImpl.java:222)
			at org.nuxeo.ecm.core.event.test.virusscan.listeners.VirusScannerProcessor.handleEventPostprocessing(VirusScannerProcessor.java:118)
			at org.nuxeo.ecm.core.event.impl.AbstractLongRunningListener.handleEvent(AbstractLongRunningListener.java:93)
			at org.nuxeo.ecm.core.event.impl.AsyncEventExecutor$ListenerWork.work(AsyncEventExecutor.java:219)
			at org.nuxeo.ecm.core.work.AbstractWork.runWorkWithTransaction(AbstractWork.java:379)
			at org.nuxeo.ecm.core.work.AbstractWork.run(AbstractWork.java:338)
			at org.nuxeo.ecm.core.work.WorkHolder.run(WorkHolder.java:57)
			at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
			at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
			at java.lang.Thread.run(Thread.java:745)
		Suppressed: org.nuxeo.ecm.core.api.CoreSessionService$CoreSessionRegistrationInfo: CoreSessionDebugInfo(Nuxeo-Work-default-2:3873888109795770.958561037, test/system#1532)
			at org.nuxeo.ecm.core.api.CoreSessionServiceImpl.createCoreSession(CoreSessionServiceImpl.java:44)
			at org.nuxeo.ecm.core.api.CoreInstance.openCoreSession(CoreInstance.java:163)
			at org.nuxeo.ecm.core.api.CoreInstance.openCoreSessionSystem(CoreInstance.java:98)
			at org.nuxeo.ecm.core.event.impl.ReconnectedEventBundleImpl.getReconnectedCoreSession(ReconnectedEventBundleImpl.java:93)
			at org.nuxeo.ecm.core.event.impl.ReconnectedEventBundleImpl.getReconnectedEvents(ReconnectedEventBundleImpl.java:111)
			at org.nuxeo.ecm.core.event.impl.ReconnectedEventBundleImpl.iterator(ReconnectedEventBundleImpl.java:222)
			at org.nuxeo.ecm.core.event.test.virusscan.listeners.VirusScannerProcessor.handleEventPostprocessing(VirusScannerProcessor.java:118)
			at org.nuxeo.ecm.core.event.impl.AbstractLongRunningListener.handleEvent(AbstractLongRunningListener.java:93)
			at org.nuxeo.ecm.core.event.impl.AsyncEventExecutor$ListenerWork.work(AsyncEventExecutor.java:219)
			at org.nuxeo.ecm.core.work.AbstractWork.runWorkWithTransaction(AbstractWork.java:379)
			at org.nuxeo.ecm.core.work.AbstractWork.run(AbstractWork.java:338)
			at org.nuxeo.ecm.core.work.WorkHolder.run(WorkHolder.java:57)
			at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
			at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
			at java.lang.Thread.run(Thread.java:745)