Fix xunit_android sample code

```ruby
$ ruby xunit_android.rb 
Loaded suite xunit_android
Started
Debug is: false
Version is: 4.4.2
.

Finished in 17.295088 seconds.

1 tests, 1 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed

0.06 tests/s, 0.06 assertions/s
```