Try bumping the test time limit to 45 seconds

Again, this is to accomodate the "dispatchmp" test on slower
machines (it takes 14-15 seconds on a modern machine).

src-test/ch/usi/dag/disl/test/utils/Runner.java

@@ -18,7 +18,7 @@ import ch.usi.dag.util.Strings;
 public abstract class Runner {
 
     protected static final Duration _INIT_TIME_LIMIT_ = Duration.of (3, SECONDS);
-    protected static final Duration _TEST_TIME_LIMIT_ = Duration.of (20, SECONDS);
+    protected static final Duration _TEST_TIME_LIMIT_ = Duration.of (45, SECONDS);
     protected static final Duration _WATCH_DELAY_ = Duration.of (100, MILLISECONDS);
 
     protected static final String _ENV_JAVA_HOME_ = "JAVA_HOME";