[clang] Generating procedures only if there isn't a spec for them already.

Summary:
Generating procedures only if there isn't a spec for them already.
This is important for incremental analysis.

infer/src/clang/cMethod_decl.ml

@@ -147,6 +147,10 @@ struct
     list_iter (process_one_method_decl tenv cg cfg curr_class namespace) decl_list
 
   let process_getter_setter context procname =
+    (*If there is already a spec for the method we want to generate (in incremental analysis) *)
+    (* we don't need to generate it again. *)
+    if Specs.summary_exists procname then false
+    else
       let class_name = Procname.c_get_class procname in
       let open CContext in
       let cls = CContext.create_curr_class context.tenv class_name in