cs: fix transparent internal structure types

Commit d96273bc0a broke internal "system" structures in the expander
that need to be transparent.

racket/src/bc/src/struct.c

@@ -5167,7 +5167,7 @@ Scheme_Object *scheme_make_struct_type_from_string(const char *name,
                         guard);
 
   if (scheme_starting_up)
-    /* Force allocation for a struc<ture type that may be in the master GC: */
+    /* Force allocation for a structure type that may be in the master GC: */
     scheme_force_struct_type_info((Scheme_Struct_Type *)r);
 
   return r;

racket/src/cs/rumble/struct.ss

@@ -605,7 +605,8 @@
           ;; Finish checking and install new property values:
           (install-props! rtd parent-rtd* all-immutables)
           ;; Record inspector
-          (unless (pair? name) ; pair implies a system structure type
+          (unless (and (pair? name) ; pair implies a system structure type
+                       insp)
             (inspector-set! rtd insp))
           ;; Register guard
           (register-guards! rtd parent-rtd guard 'at-start))))]))