make a simple type predicate, and not an instance - else lowtag 3 is …

…checked via deftransform

src/code/primordial-type.lisp

@@ -53,7 +53,7 @@
   (frob instance *instance-type*)
   (frob funcallable-instance *funcallable-instance-type*)
   ;; New after sbcl-2.4.7: User-defined integers, to be used in DEFMETHOD etc.
-  (frob udef-inttype *instance-type*)
+  #+(or) (frob udef-inttype *instance-type*)
   ;; new in sbcl-1.0.3.3: necessary to act as a join point for the
   ;; extended sequence hierarchy.  (Might be removed later if we use
   ;; a dedicated FUNDAMENTAL-SEQUENCE class for this.)

src/compiler/x86-64/type-vops.lisp

@@ -532,6 +532,7 @@
                 (:generator 1 (inst cmp :byte value ,widetag)))))
   (define single-float-p single-float-widetag)
   (define characterp character-widetag)
+  (define udef-inttype-p udef-inttype-lowtag)
   (define unbound-marker-p unbound-marker-widetag))
 
 ;;; FUNCTIONP, LISTP, %INSTANCEP, %OTHER-POINTER-P produce a flag result
@@ -546,7 +547,6 @@
   (define functionp fun-pointer-lowtag)
   (define listp list-pointer-lowtag)
   (define %instancep instance-pointer-lowtag)
-  (define udef-inttype-p udef-inttype-lowtag)
   (define %other-pointer-p other-pointer-lowtag))
 
 ;;; Function subtypes produce a flag result