[SYCL] Fix reductions not working inside graph

* Graph submission now properly creates a host visible event on the command list allowing auxilliary resources to be cleaned up

* executeCommandList slightly modified to block execution only for command lists not allowed to be batched.

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -1583,9 +1583,11 @@ void _pi_queue::CaptureIndirectAccesses() {
 pi_result _pi_queue::executeCommandList(pi_command_list_ptr_t CommandList,
                                         bool IsBlocking,
                                         bool OKToBatchCommand) {
-  // When executing a Graph, defer execution
-  if( this->Properties & PI_EXT_ONEAPI_QUEUE_LAZY_EXECUTION ) return PI_SUCCESS;
-
+  // When executing a Graph, defer execution if this is a command
+  // which could be batched (i.e. likely a kernel submission)
+  if (this->Properties & PI_EXT_ONEAPI_QUEUE_LAZY_EXECUTION && OKToBatchCommand)
+    return PI_SUCCESS;
+
   bool UseCopyEngine = CommandList->second.isCopy(this);
 
   // If the current LastCommandEvent is the nullptr, then it means
@@ -3827,31 +3829,13 @@ pi_result piQueueFinish(pi_queue Queue) {
 // so this can be left as a no-op.
 pi_result piQueueFlush(pi_queue Queue) {
   if( Queue->Properties & PI_EXT_ONEAPI_QUEUE_LAZY_EXECUTION ) {
+
     pi_command_list_ptr_t CommandList{};
     // TODO: 
     CommandList = Queue->LazyCommandListMap.begin();
-
-    auto &ZeCommandQueue = CommandList->second.ZeQueue;
-    // Scope of the lock must be till the end of the function, otherwise new mem
-    // allocs can be created between the moment when we made a snapshot and the
-    // moment when command list is closed and executed. But mutex is locked only
-    // if indirect access tracking enabled, because std::defer_lock is used.
-    // unique_lock destructor at the end of the function will unlock the mutex
-    // if it was locked (which happens only if IndirectAccessTrackingEnabled is
-    // true).
-    std::unique_lock<pi_shared_mutex> ContextsLock(
-      Queue->Device->Platform->ContextsMutex, std::defer_lock);
-
-    // Close the command list and have it ready for dispatch.
-    ZE_CALL(zeCommandListClose, (CommandList->first));
-
-    // Offload command list to the GPU for asynchronous execution
-    auto ZeCommandList = CommandList->first;
-    auto ZeResult = ZE_CALL_NOCHECK(
-        zeCommandQueueExecuteCommandLists,
-        (ZeCommandQueue, 1, &ZeCommandList, CommandList->second.ZeFence));
+
+    Queue->executeCommandList(CommandList, false, false);
   }
-  (void)Queue;
   return PI_SUCCESS;
 }