add ending message in paddle_build.sh (#20334)

* add ending message

Add ending message to indicate script execution properly finished

* Update paddle_build.sh

test=develop

* Update paddle_build.sh

test=document_fix

* Update paddle_build.sh

test=develop test=document_fix

paddle/scripts/paddle_build.sh

@@ -1134,6 +1134,7 @@ function main() {
         exit 1
         ;;
       esac
+      echo "paddle_build script finished as expected"
 }
 
 main $@