Bad error message for define-like things

[dvanhorn]

This gives a bad syntax error:

#lang class/0
(define-class a%
  (define/asdf (m) 1))

which is

define-class: There were multiple syntax errors. The first error follows:
expected the identifier `isl+:check-range' in: define/asdf

Obviously the isl+:check-range is a nasty implementation artifact.