schemify: fix undefined checking when constants no enforced

Related to #3325

pkgs/racket-test-core/tests/racket/module.rktl

@@ -1029,6 +1029,12 @@
     (err/rt-test (eval '(module m racket/base (define x 2) (provide x)))
                  exn:fail:contract:variable?)))
 
+(parameterize ([current-namespace (make-base-namespace)])
+  (parameterize ([compile-enforce-module-constants #f])
+    (eval '(module m racket/base (eq? y y) (define y 2))))
+  (err/rt-test/once (eval '(dynamic-require ''m #f))
+                    exn:fail:contract:variable?))
+
 ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Check JIT treatement of seemingly constant imports
 

racket/src/cs/schemified/schemify.scm

@@ -17438,7 +17438,7 @@
                                                         app_0
                                                         (if enforce-constant?_0
                                                           'not-ready
-                                                          'set!ed)))
+                                                          'set!ed-too-early)))
                                                      (for-loop_1 rest_1))))
                                                (values)))))))
                                       (for-loop_1 ids_0)))

racket/src/schemify/mutated.rkt

@@ -42,7 +42,7 @@
                                             'not-ready
                                             ;; If constants should not be enforced, then
                                             ;; treat all variable as mutated:
-                                            'set!ed)))]
+                                            'set!ed-too-early)))]
       [`,_ (void)]))
   ;; Walk through the body:
   (for/fold ([prev-knowns knowns]) ([form (in-list l)])