Temp fix for upgrader (pytorch#78589)

Summary: see: https://fb.workplace.com/groups/pytorch.edge.users/permalink/1086950342175258/

Test Plan: https://www.internalfb.com/phabricator/paste/view/P503629793

Reviewed By: qihqi

Differential Revision: D36694318

Pull Request resolved: pytorch#78589
Approved by: https://github.com/qihqi

torch/csrc/jit/serialization/flatbuffer_serializer_jit.cpp

@@ -1,6 +1,7 @@
 #include <torch/csrc/jit/serialization/flatbuffer_serializer_jit.h>
 
 #include <torch/csrc/jit/mobile/flatbuffer_loader.h>
+#include <torch/csrc/jit/operator_upgraders/upgraders_entry.h>
 #include <torch/csrc/jit/serialization/export.h>
 #include <torch/csrc/jit/serialization/export_bytecode.h>
 #include <torch/csrc/jit/serialization/flatbuffer_serializer.h>
@@ -14,6 +15,9 @@ Module parse_and_initialize_jit_module(
     size_t size,
     ExtraFilesMap& extra_files,
     c10::optional<at::Device> device) {
+#if ENABLE_UPGRADERS
+  populate_upgraders_graph_map();
+#endif
   auto* flatbuffer_module = mobile::serialization::GetMutableModule(data.get());
   FlatbufferLoader loader;
   mobile::Module mobilem = loader.parseModule(flatbuffer_module);