EJB CalendarBasedTimeoutTestCase assertion type must match

Currently some booleans are checked with assertNotNull, i.E. https://github.com/wildfly/wildfly/blob/24.0.1.Final/ejb3/src/test/java/org/jboss/as/ejb3/timer/schedule/CalendarBasedTimeoutTestCase.java#L389

Fix: Adopt correct assert for the relevant type.