In OpenCLCtxScope::SetEvent, the necessary clRetainEvent

call was inside an assert, thus never called if NDEBUG
was defined.  This change asserts only on the return value
of the function, as in other parts of the code.

TracyOpenCL.hpp

@@ -261,7 +261,8 @@ namespace tracy {
         tracy_force_inline void SetEvent(cl_event event)
         {
             m_event = event;
-            assert(clRetainEvent(m_event) == CL_SUCCESS);
+            cl_int err = clRetainEvent(m_event);
+            assert(err == CL_SUCCESS);
             m_ctx->GetQuery(m_beginQueryId).event = m_event;
         }