repair for re-expansion of an implicit-form expansion

The repair in 385f9588f8 propagates the
must-be-bound callback too far. It shouldn't be propagated anymore after
a non-rename transformer is applied.

Closes #2048

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

@@ -1950,6 +1950,16 @@
                  (let-syntax ([#%datum (make-rename-transformer #'unbound)])
                    (+ 1 2))))
 
+(module make-sure-not-bound-as-syntax-is-not-propagated-to-reexpansion racket/base
+  (module new-top racket/base
+    (provide #%top)
+    (define (helper sym) sym)
+    (define-syntax-rule (#%top . ID)
+      (helper 'ID)))
+  
+  (local-require (submod 'new-top))
+  foobar)
+
 ;; ----------------------------------------
 ;; Check that definition context bindings are made available when the context is provided as fourth
 ;; argument of syntax-local-bind-syntaxes

racket/src/expander/expand/main.rkt

@@ -322,7 +322,7 @@
                                                             id))
                    #:skip-log? (or (expand-context-only-immediate? ctx)
                                    (rename-transformer? t))
-                   #:fail-non-transformer fail-non-transformer)])]))
+                   #:fail-non-transformer (and (rename-transformer? t) fail-non-transformer))])]))
 
 ;; Handle the expansion of a variable to itself
 (define (dispatch-variable t s id ctx binding primitive? protected?)

racket/src/racket/src/startup.inc

@@ -39985,11 +39985,12 @@ static const char *startup_source =
 "(let-values(((or-part_263)"
 "(expand-context-only-immediate? ctx_23)))"
 "(if or-part_263 or-part_263(1/rename-transformer? t_53))))"
-"((fail-non-transformer199_0) fail-non-transformer_4))"
+"((temp199_0)"
+"(if(1/rename-transformer? t_53) fail-non-transformer_4 #f)))"
 "(expand9.1"
 " temp197_0"
 " #t"
-" fail-non-transformer199_0"
+" temp199_0"
 " #t"
 " temp198_0"
 " #t"