Remove redundant median method

This is not required as the distribution overrides the probability(x0,
x1) method.

commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/NormalDistribution.java

@@ -193,14 +193,6 @@ public boolean isSupportConnected() {
         return true;
     }
 
-    /** {@inheritDoc} */
-    @Override
-    protected double getMedian() {
-        // Overridden for the probability(double, double) method.
-        // This is intentionally not a public method.
-        return mean;
-    }
-
     /** {@inheritDoc} */
     @Override
     public ContinuousDistribution.Sampler createSampler(final UniformRandomProvider rng) {