Fix TaskLogCleanTest#testDeleteLogsByDate - flaky tests when dealing with range of dates (Windows OS)

We're facing some random failures due to the following test execution:

https://github.com/kiegroup/jbpm/blob/master/jbpm-test-coverage/src/test/java/org/jbpm/test/functional/log/TaskLogCleanTest.java#L122

From time to time, we can see test failures such as https://rhba-qe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/job/BxMS/job/RHPAM-7.11-nightly/job/certification/job/community-tests/job/blessed-community-tests-jbpm-jvmos-matrix/lastCompletedBuild/jdk=jdk1.8,label_exp=w2k16/testReport/org.jbpm.test.functional.log/TaskLogCleanTest/testDeleteLogsByDate/

output.log

Seems to be related to the fact that some Windows OS based machines are extremely fast when executing the tests and this might lead to records being created at the exact same time making the test fail.