8353331: Test ForkJoinPool20Test::testFixedDelaySequence is failing

Reviewed-by: dl, vklang

Author: Alan Bateman

test/jdk/java/util/concurrent/tck/ForkJoinPool20Test.java

@@ -450,7 +450,6 @@ public void realRun() {
                         if (elapsedMillis >= (done.getCount() == cycles ? d : 2 * d))
                                 tryLongerDelay.set(true);
                         previous.set(now);
-                        assertTrue(done.getCount() > 0);
                         done.countDown();
                     }};
                 final ScheduledFuture<?> periodicTask =