MATCH-83 & MATCH-84: vector patterns with rest pattern broken

aim for correctness, the attempt to share tests between vector
patterns with and without rest patterns was problematic. We'll
reconsider this optimization at some future point.

src/main/clojure/clojure/core/match.clj

@@ -1595,11 +1595,8 @@ col with the first column and compile the result"
 
 (defmethod groupable? [VectorPattern VectorPattern]
   [a b]
-  (cond
-    (= (:size a) (:size b)) true
-    (and (:rest? a) (<= (:size a) (:size b))) true
-    (and (:rest? b) (<= (:size b) (:size a))) true
-    :else false))
+  (and (= (:rest? a) (:rest? b))
+       (= (:size a) (:size b))))
 
 ;; =============================================================================
 ;; # Interface