Fixing issue 40.

Author: lemire

fastfilter/src/main/java/org/fastfilter/utils/Hash.java

@@ -32,7 +32,7 @@ public static long randomSeed() {
      */
     public static int reduce(int hash, int n) {
         // http://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
-        return (int) (((hash & 0xffffffffL) * n) >>> 32);
+        return (int) (((hash & 0xffffffffL) * (n & 0xffffffffL)) >>> 32);
     }
 
     /**

fastfilter/src/test/java/org/fastfilter/TestAllFilters.java

@@ -183,9 +183,6 @@ private static void test(TestFilterType type, int len, int seed, boolean log) {
             }
             time = System.nanoTime() - time;
             nanosPerRemove = time / len;
-if (f.cardinality() != 0) {
-    System.out.println(f.cardinality());
-}
             assertEquals(f.toString(), 0, f.cardinality());
         }
         if (log) {