Remove useless alert.

examples/performance-test.html

@@ -15,8 +15,7 @@
     <script type="text/javascript" src="../src/core/Matrix4.old.js"></script>
     <script type="text/javascript">
     function initTest() {
-      alert("hello");
-      var times = 50000;
+      var times = 5000000;
       //Vector2
       console.time("Vector2 x " + times);
       for( var i = 0; i < times; ++i) {