JS backend: remove ECMA 3, but several tests is broken.

Main reason: overload extention property:

Int.bar = 1
String.bar = 2

libraries/examples/browser-example/sample.html

@@ -9,7 +9,7 @@
 </div>
 
 <script type="text/javascript" src="src/js/jquery.js"></script>
-<script src="../../../dist/kotlinc/lib/kotlinEcma3.js"></script>
+<script src="../../../dist/kotlinc/lib/kotlin.js"></script>
 <script type="text/javascript" src="target/js/browser-example.js"></script>
 
 <!--