Update Issue879Test.java

Reduce the number of tests

Author: marci4

src/test/java/org/java_websocket/issues/Issue879Test.java

@@ -53,7 +53,7 @@
 @RunWith(Parameterized.class)
 public class Issue879Test {
 
-    private static final int NUMBER_OF_TESTS = 40;
+    private static final int NUMBER_OF_TESTS = 20;
 
     @Parameterized.Parameter
     public int numberOfConnections;