fix js event test

Author: dcodeIO

test/binaryen.js/event.js

@@ -7,7 +7,9 @@ function cleanInfo(info) {
 }
 
 var module = new binaryen.Module();
-module.setFeatures(binaryen.Features.ExceptionHandling | binaryen.Features.Multivalue);
+module.setFeatures(binaryen.Features.ReferenceTypes |
+                   binaryen.Features.ExceptionHandling |
+                   binaryen.Features.Multivalue);
 
 var pairType = binaryen.createType([binaryen.i32, binaryen.f32]);