fixes a Fate bug:

fixes an issue with how new fate transaction runners are created if one dies. Prior to this commit, the check for dead transaction runners would only occur once. This now occurs periodically.

core/src/main/java/org/apache/accumulo/core/fate/Fate.java

@@ -246,7 +246,7 @@ public void startTransactionRunners(AccumuloConfiguration conf) {
         Property.MANAGER_FATE_THREADPOOL_SIZE, true);
     fatePoolWatcher =
         ThreadPools.getServerThreadPools().createGeneralScheduledExecutorService(conf);
-    ThreadPools.watchCriticalScheduledTask(fatePoolWatcher.schedule(() -> {
+    ThreadPools.watchCriticalScheduledTask(fatePoolWatcher.scheduleWithFixedDelay(() -> {
       // resize the pool if the property changed
       ThreadPools.resizePool(pool, conf, Property.MANAGER_FATE_THREADPOOL_SIZE);
       // If the pool grew, then ensure that there is a TransactionRunner for each thread
@@ -268,7 +268,7 @@ public void startTransactionRunners(AccumuloConfiguration conf) {
           }
         }
       }
-    }, 3, SECONDS));
+    }, 3, 30, SECONDS));
     executor = pool;
   }