message: Also add a test for quantile in window function
diff: @@ -60,3 +60,20 @@ NULL 1
  7 7
  8 8
  9 8
  +
  +query II
  +SELECT r, quantile(r, 0.5) over (order by r rows between 1 preceding and 3 following) FROM quantile ORDER BY 1, 2
  +----
  +NULL 0
  +NULL 0
  +NULL 1
  +0 1
  +1 2
  +2 3
  +3 4
  +4 5
  +5 6
  +6 7
  +7 7
  +8 8
  +9 8
  