add more tick to slow down rpc requests

lolnode/lib/state/resyncing.dart

@@ -51,6 +51,7 @@ class ReSyncingState extends AppStateAutomata {
       final int _height = await rpc.height();
       return SyncedState(appHook, _height, pageIndex);
     } else {
+      await tick();
       return this;
     }
 

lolnode/lib/state/synced.dart

@@ -104,6 +104,7 @@ class SyncedState extends AppStateAutomata {
       return ReSyncingState(appHook, pageIndex);
     }
 
+    await tick();
     // log.finer('SyncedState: checkSync loop');
     height = await rpc.height();
     connected = await daemon.isConnected();

lolnode/lib/state/syncing.dart

@@ -47,6 +47,7 @@ class SyncingState extends AppStateAutomata {
       final int _height = await rpc.height();
       return SyncedState(appHook, _height, config.defaultPageIndex);
     } else {
+      await tick();
       return this;
     }
   }