[NO ISSUE][STO] Make IO operation completed state volatile

- user model changes: no
- storage format changes: no
- interface changes: no

Details:

- To avoid a deadlock between checking an IO operation completed
  state and scheduling another flush operation using the same
  IO scheduler, make the IO operation state volatile rather
  synchronizing on the operation.

Change-Id: Ibef0fe3dc52a5a6b36cc29bbac0fb38936944cee
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/15663
Reviewed-by: Ali Alsuliman <ali.al.solaiman@gmail.com>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>

hyracks-fullstack/hyracks/hyracks-storage-am-lsm-common/src/main/java/org/apache/hyracks/storage/am/lsm/common/impls/AbstractIoOperation.java

@@ -44,7 +44,7 @@ public abstract class AbstractIoOperation implements ILSMIOOperation {
     private volatile Throwable failure;
     private LSMIOOperationStatus status = LSMIOOperationStatus.SUCCESS;
     private ILSMDiskComponent newComponent;
-    private boolean completed = false;
+    private volatile boolean completed = false;
     private List<IoOperationCompleteListener> completeListeners;
 
     private final AtomicBoolean isActive = new AtomicBoolean(true);
@@ -203,7 +203,7 @@ public boolean isActive() {
     }
 
     @Override
-    public synchronized boolean isCompleted() {
+    public boolean isCompleted() {
         return completed;
     }