* polish some error message in framework, test=develop

* fix unittest error, test=develop

* replace PADDLE_ENFORCE, test=develop

* polish details based review comment, test=develop

Add examples for error message writing specification - NotFound, OutOfRange, AlreadyExists, PermissionDenied (#21134)

* add examples for error msg spec, test=develop

* change ENFORCE to ENFORCE_**, test=develop

* add more already exists examples, test=develop

test=develop

test=develop