Flaky test fix for org.kie.server.services.taskassigning.planning.TaskAssigningPlanningKieServerExtensionTest#initRuntimeClientWithKeyStore

org.kie.server.services.taskassigning.planning.TaskAssigningPlanningKieServerExtensionTest#initRuntimeClientWithKeyStore]

is failing as it depends on a singleton class which sometimes is already loaded, so the new values from system properties are not loaded when running test cases. Thus, surefire maven plugin requires to configured to execute each test within its own jvm fork.