Add a flag for HttpRemoteTask to avoid eager but unnecessary sendUpdate

It should not sendUpdate before task been started,
while the needsUpdate flag in RemoteHttpTask is not enough to ensure this,
which case will happen on all non-leaf stage, as 450-470 lines in
SqlStageExecution.java
Although task will start soon after noMoreSplits, but we should avoid
this, which is unnecessary and not strictly accurate in principle.

core/trino-main/src/main/java/io/trino/server/remotetask/HttpRemoteTask.java

@@ -159,6 +159,7 @@ public final class HttpRemoteTask
 
     private final PartitionedSplitCountTracker partitionedSplitCountTracker;
 
+    private final AtomicBoolean started = new AtomicBoolean(false);
     private final AtomicBoolean aborting = new AtomicBoolean(false);
 
     public HttpRemoteTask(
@@ -318,6 +319,7 @@ public void start()
     {
         try (SetThreadName ignored = new SetThreadName("HttpRemoteTask-%s", taskId)) {
             // to start we just need to trigger an update
+            started.set(true);
             scheduleUpdate();
 
             dynamicFiltersFetcher.start();
@@ -513,7 +515,7 @@ private synchronized void sendUpdate()
     {
         TaskStatus taskStatus = getTaskStatus();
         // don't update if the task hasn't been started yet or if it is already finished
-        if (!needsUpdate.get() || taskStatus.getState().isDone()) {
+        if (!started.get() || !needsUpdate.get() || taskStatus.getState().isDone()) {
             return;
         }