PersistentIntervalTimerManagementTestCase fails on slower machine

How reproducible:
10%, with higher CPU load or slower machine

Steps to Reproduce:
1. ./integration-tests.sh -Dts.noSmoke -Dts.basic -Dtest=PersistentIntervalTimerManagementTestCase

Actual results:
Timer should fire twice! expected:<2> but was:<3>
java.lang.AssertionError: Timer should fire twice! expected:<2> but was:<3>
at org.junit.Assert.fail(Assert.java:88)
at org.junit.Assert.failNotEquals(Assert.java:743)
at org.junit.Assert.assertEquals(Assert.java:118)
at org.junit.Assert.assertEquals(Assert.java:555)
at org.jboss.as.test.integration.ejb.timerservice.mgmt.AbstractTimerManagementTestCase.testSuspendAndTrigger(AbstractTimerManagementTestCase.java:149)
at org.jboss.as.test.integration.ejb.timerservice.mgmt.PersistentIntervalTimerManagementTestCase.testSuspendAndTrigger(PersistentIntervalTimerManagementTestCase.java:73)

Expected results:
No failures in test case.