Fix analysis predictor when loading the persistable RAW type variable. (#15613)

Author: qingqing01

paddle/fluid/inference/api/analysis_predictor.cc

@@ -58,7 +58,8 @@ namespace {
 bool IsPersistable(const framework::VarDesc *var) {
   if (var->Persistable() &&
       var->GetType() != framework::proto::VarType::FEED_MINIBATCH &&
-      var->GetType() != framework::proto::VarType::FETCH_LIST) {
+      var->GetType() != framework::proto::VarType::FETCH_LIST &&
+      var->GetType() != framework::proto::VarType::RAW) {
     return true;
   }
   return false;