[modules] Factor out cell load into helper function.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index b9366c18acbac87f4a19fb76d7b2e5197129b304..779f67730584d4dc7b4fb0705f95b2cf990ff38b 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6733,6 +6733,7 @@ class Module : public Struct {
   // Implementation of spec operation ModuleEvaluation.
   static MUST_USE_RESULT MaybeHandle<Object> Evaluate(Handle<Module> module);
 
+  Cell* GetCell(int cell_index);
   static Handle<Object> LoadVariable(Handle<Module> module, int cell_index);
   static void StoreVariable(Handle<Module> module, int cell_index,
                             Handle<Object> value);