test: fix deprecation warning in addons test

The non-isolate version of node::FatalException() is deprecated, switch
to the version that takes an isolate as its first argument.

PR-URL: #1793
Reviewed-By: Trevor Norris <[email protected]>

Author: bnoordhuis

test/addons/async-hello-world/binding.cc

@@ -39,7 +39,7 @@ void AfterAsync(uv_work_t* r) {
   delete req;
 
   if (try_catch.HasCaught()) {
-    FatalException(try_catch);
+    FatalException(isolate, try_catch);
   }
 }