[L0] Maintain Lock of Queue while syncing the Last Command Event

- To avoid usecases where the LastcommandEvent could be updated in
  another thread and a thread can be expecting the Queue Wait to include
this event, then hold the queue lock such that the last command event
remains unchanged during synchronization.

Signed-off-by: Neil R. Spruit <neil.r.spruit@intel.com>

Author: nrspruit

source/adapters/level_zero/queue.cpp

@@ -1697,14 +1697,7 @@ ur_result_t ur_queue_handle_t_::synchronize() {
     // zero handle can have device scope, so we can't synchronize the last
     // event.
     if (isInOrderQueue() && !LastCommandEvent->IsDiscarded) {
-      if (UrL0QueueSyncNonBlocking) {
-        auto SyncZeEvent = LastCommandEvent->ZeEvent;
-        this->Mutex.unlock();
-        ZE2UR_CALL(zeHostSynchronize, (SyncZeEvent));
-        this->Mutex.lock();
-      } else {
-        ZE2UR_CALL(zeHostSynchronize, (LastCommandEvent->ZeEvent));
-      }
+      ZE2UR_CALL(zeHostSynchronize, (LastCommandEvent->ZeEvent));
 
       // clean up all events known to have been completed as well,
       // so they can be reused later