restore the exception caught since it is necessary for python call stack (#16160)

test=develop

paddle/fluid/framework/operator.cc

@@ -186,14 +186,14 @@ void OperatorBase::Run(const Scope& scope, const platform::Place& place) {
     VLOG(3) << place << " " << DebugStringEx(&scope);
   } catch (platform::EnforceNotMet exception) {
     if (Attrs().count("sub_block") != 0) {
-      throw;
+      throw std::move(exception);
     }
 
     auto& callstack = Attr<std::vector<std::string>>(
         OpProtoAndCheckerMaker::OpCreationCallstackAttrName());
 
     if (callstack.empty()) {
-      throw;
+      throw std::move(exception);
     }
     std::ostringstream sout;
     sout << "Invoke operator " << Type() << " error.\n";
@@ -204,7 +204,7 @@ void OperatorBase::Run(const Scope& scope, const platform::Place& place) {
     sout << "C++ Callstacks: \n";
     sout << exception.err_str_;
     exception.err_str_ = sout.str();
-    throw;
+    throw std::move(exception);
   } catch (...) {
     std::rethrow_exception(std::current_exception());
   }