Add missing permutation benchmark to *-papi (#515)

A backpack, A backpack, My kingdom for a backpack!

vector-bench-papi/benchmarks/Main.hs

@@ -11,6 +11,7 @@ import Bench.Vector.Algo.Quickhull  (quickhull)
 import Bench.Vector.Algo.Spectral   (spectral)
 import Bench.Vector.Algo.Tridiag    (tridiag)
 import Bench.Vector.Algo.FindIndexR (findIndexR, findIndexR_naive, findIndexR_manual)
+import Bench.Vector.Algo.NextPermutation (generatePermTests)
 
 import Bench.Vector.TestData.ParenTree (parenTree)
 import Bench.Vector.TestData.Graph     (randomGraph)
@@ -49,6 +50,7 @@ main = do
   !ds <- randomVector useSize
   !sp <- randomVector (floor $ sqrt $ fromIntegral useSize)
   vi <- MV.new useSize
+  permTests <- generatePermTests gen useSize
 
   defaultMainWithIngredients ingredients $ bgroup "All"
     [ bench "listRank"   $ whnf listRank useSize
@@ -65,4 +67,5 @@ main = do
     , bench "findIndexR_manual" $ whnf findIndexR_manual ((<indexFindThreshold), as)
     , bench "minimumOn"  $ whnf (U.minimumOn (\x -> x*x*x)) as
     , bench "maximumOn"  $ whnf (U.maximumOn (\x -> x*x*x)) as
+    , bgroup "(next|prev)Permutation" $ map (\(name, act) -> bench name $ whnfIO act) permTests
     ]