Fix thread reinitialize in time-series source operator (#108751) (#10…

…8813)

Currently, we only reinitialize the Lucene internal of the new top if 
the tsid changes. This isn't enough. We should always ensure the new top
is reinitialized if necessary, regardless of tsid.

Closes #108727

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/lucene/TimeSeriesSortedSourceOperatorFactory.java

@@ -292,10 +292,14 @@ void consume() throws IOException {
                             queue.pop();
                             newTop = queue.size() > 0 ? queue.top() : null;
                         }
-                        if (newTop != null && newTop.timeSeriesHash.equals(currentTsid) == false) {
-                            newTop.reinitializeIfNeeded(Thread.currentThread());
-                            globalTsidOrd++;
-                            currentTsid = BytesRef.deepCopyOf(newTop.timeSeriesHash);
+                        if (newTop != null) {
+                            if (newTop != leaf) {
+                                newTop.reinitializeIfNeeded(Thread.currentThread());
+                            }
+                            if (newTop.timeSeriesHash.equals(currentTsid) == false) {
+                                globalTsidOrd++;
+                                currentTsid = BytesRef.deepCopyOf(newTop.timeSeriesHash);
+                            }
                         }
                     }
                 } else {