[L0]: Fix Out Event in Enqueue Wait Events to prevent reuse

- Fix Out Event created in Enqueue Wait Events to ensure the event is
  not reused and is kept linked to the enqueue wait events even after
being completed.

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

Author: nrspruit

source/adapters/level_zero/event.cpp

@@ -147,6 +147,9 @@ ur_result_t urEnqueueEventsWait(
   }
   if (OutEvent && (*OutEvent)->Completed) {
     UR_CALL(CleanupCompletedEvent((*OutEvent), false, false));
+    // This event cannot be cached and cannot be deleted until the user is done
+    // with the event handle.
+    (*OutEvent)->CannotCache = true;
     UR_CALL(urEventReleaseInternal((*OutEvent)));
   }
 
@@ -795,7 +798,7 @@ urEventWait(uint32_t NumEvents, ///< [in] number of events in the event list
       //
       ur_event_handle_t_ *Event = ur_cast<ur_event_handle_t_ *>(e);
       if (!Event->hasExternalRefs())
-        die("urEventsWait must not be called for an internal event");
+        die("urEventWait must not be called for an internal event");
 
       ze_event_handle_t ZeHostVisibleEvent;
       if (auto Res = Event->getOrCreateHostVisibleEvent(ZeHostVisibleEvent))
@@ -1137,7 +1140,8 @@ ur_result_t urEventReleaseInternal(ur_event_handle_t Event) {
   if (DisableEventsCaching || !Event->OwnNativeHandle) {
     delete Event;
   } else {
-    Event->Context->addEventToContextCache(Event);
+    if (!Event->CannotCache)
+      Event->Context->addEventToContextCache(Event);
   }
 
   // We intentionally incremented the reference counter when an event is

source/adapters/level_zero/event.hpp

@@ -256,6 +256,9 @@ struct ur_event_handle_t_ : _ur_object {
   bool CounterBasedEventsEnabled = false;
   // Keeps track of whether we are using Interrupt-based Events.
   bool InterruptBasedEventsEnabled = false;
+  // Indicates if this event can be cached or if the event needs to exist until
+  // the handle is released.
+  bool CannotCache = false;
 };
 
 // Helper function to implement zeHostSynchronize.