Remove test from Octave testsuite.

The function is only called by Matlab if the statistics toolbox is not available.

(cherry picked from commit ac3af205)

matlab/missing/stats-matlab/quantile.m

@@ -236,6 +236,12 @@ y = ipermute(y,order);
 
 
 %@test:1
+%$ if isoctave()
+%$   t = true;
+%$   T = t;
+%$   LOG = NaN;
+%$   return
+%$ end
 %$ X = randn(10000000, 1);
 %$
 %$ try