[infer][biabduction] clear the error log when creating a specialized clone of a method

Summary: This removes cases of duplicated warnings when the dynamic dispatch handling specializes a method Infer already reported on.

Reviewed By: sblackshear

Differential Revision: D6060337

fbshipit-source-id: dbefeca

infer/src/IR/Cfg.ml

@@ -417,7 +417,8 @@ let specialize_types callee_pdesc resolved_pname args =
       ~init:([], Mangled.Map.empty) callee_attributes.formals args
   in
   let resolved_attributes =
-    {callee_attributes with formals= List.rev resolved_params; proc_name= resolved_pname}
+    { callee_attributes with
+      formals= List.rev resolved_params; proc_name= resolved_pname; err_log= Errlog.empty () }
   in
   Attributes.store resolved_attributes ;
   let resolved_pdesc =