Remove hppc from task manager (#85889)

The task manager uses hppc to keep track of the count of child tasks for
each network connection. This is bookkeeping code and not performance
critical, nor is it memory intensive (the map won't be that large). This
commit converts the code to use a HashMap.

relates #84735

Author: rjernst

server/src/main/java/org/elasticsearch/tasks/TaskManager.java

@@ -8,9 +8,6 @@
 
 package org.elasticsearch.tasks;
 
-import com.carrotsearch.hppc.ObjectIntHashMap;
-import com.carrotsearch.hppc.ObjectIntMap;
-
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
@@ -60,8 +57,6 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Consumer;
-import java.util.stream.Collectors;
-import java.util.stream.StreamSupport;
 
 import static org.elasticsearch.core.TimeValue.timeValueMillis;
 import static org.elasticsearch.http.HttpTransportSettings.SETTING_HTTP_MAX_HEADER_SIZE;
@@ -506,7 +501,7 @@ private static class CancellableTaskHolder {
         private final CancellableTask task;
         private boolean finished = false;
         private List<Runnable> cancellationListeners = null;
-        private ObjectIntMap<Transport.Connection> childTasksPerConnection = null;
+        private Map<Transport.Connection, Integer> childTasksPerConnection = null;
         private String banChildrenReason;
         private List<Runnable> childTaskCompletedListeners = null;
 
@@ -587,15 +582,15 @@ synchronized void registerChildConnection(Transport.Connection connection) {
                 throw new TaskCancelledException("parent task was cancelled [" + banChildrenReason + ']');
             }
             if (childTasksPerConnection == null) {
-                childTasksPerConnection = new ObjectIntHashMap<>();
+                childTasksPerConnection = new HashMap<>();
             }
-            childTasksPerConnection.addTo(connection, 1);
+            childTasksPerConnection.merge(connection, 1, Integer::sum);
         }
 
         void unregisterChildConnection(Transport.Connection node) {
             final List<Runnable> listeners;
             synchronized (this) {
-                if (childTasksPerConnection.addTo(node, -1) == 0) {
+                if (childTasksPerConnection.merge(node, -1, Integer::sum) == 0) {
                     childTasksPerConnection.remove(node);
                 }
                 if (childTasksPerConnection.isEmpty() == false || this.childTaskCompletedListeners == null) {
@@ -617,9 +612,7 @@ Set<Transport.Connection> startBan(String reason, Runnable onChildTasksCompleted
                 if (childTasksPerConnection == null) {
                     pendingChildConnections = Collections.emptySet();
                 } else {
-                    pendingChildConnections = StreamSupport.stream(childTasksPerConnection.spliterator(), false)
-                        .map(e -> e.key)
-                        .collect(Collectors.toUnmodifiableSet());
+                    pendingChildConnections = Set.copyOf(childTasksPerConnection.keySet());
                 }
                 if (pendingChildConnections.isEmpty()) {
                     assert childTaskCompletedListeners == null;