rand_distr: work around tan func issue

Author: dhardy

Diff for: rand_distr/src/cauchy.rs

@@ -130,8 +130,11 @@ mod test {
             assert_eq!(buf, expected);
         }
 
+        // Warning: in a few cases, results vary slightly between different
+        // platforms, presumably due to differences in precision of system impls
+        // of the tan function. We work around this by avoiding these values.
         test_samples(100f64, 10.0, &[77.93369152808678, 90.1606912098641,
                 125.31516221323625, 86.10217834773925]);
-        test_samples(20f32, 10.0, &[27.175842, -2.0663052, 11.013268, 10.160688]);
+        test_samples(15f32, 10.0, &[22.175842, -7.066305, 6.0132685, 5.1606884]);
     }
 }