[specialization] avoid requesting a summary with empty specialization

Summary:
an empty specialization key `{alias: none, dynamic_types: { }}` will
never generate a better summary than the default summary. We make sure we never
request such specialization now. It should save us some computation time (and space).

Reviewed By: hajduakos, jvillard

Differential Revision:
D55244714

Privacy Context Container: L1208441

fbshipit-source-id: cbebad818f8f049e81418a836e1491765d680a26

infer/src/pulse/PulseCallOperations.ml

@@ -701,7 +701,9 @@ let call tenv path ~caller_proc_desc
               Specialization.Pulse.pp specialization ;
           if nth_iteration >= max_iteration then
             L.d_printfln "[specialization] we have reached the maximum number of iteration" ;
-          if nth_iteration >= max_iteration || has_already_be_given || ask_caller_of_caller_first
+          if
+            nth_iteration >= max_iteration || has_already_be_given || ask_caller_of_caller_first
+            || Specialization.Pulse.is_empty specialization
           then
             case_if_specialization_is_impossible
               ~f:(add_need_dynamic_type_specialization needs_from_caller)