apl: perf — fix quadratic append in permutations, restore queens(8)

apl-permutations was doing (append acc <new-perms>) which is
O(|acc|) and acc grows ~N! big — total cost O(N!²).

Swapped to (append <new-perms> acc) — append is O(|first|)
so cost is O((n+1)·N!_prev) per layer, total O(N!).  q(7)
went from 32s to 12s; q(8)=92 now finishes well within the
300s timeout, so the queens(8) test is restored.

497/497.  Phase 8 complete.

lib/apl/runtime.sx

@@ -883,7 +883,7 @@
       (let
         ((sub (apl-permutations (- n 1))))
         (reduce
-          (fn (acc p) (append acc (apl-insert-everywhere n p)))
+          (fn (acc p) (append (apl-insert-everywhere n p) acc))
           (list)
           sub)))))