tokens array is in the wrong order, field-item tokens don't get replaced

I discovered by reading the code that there's a very useful feature whereby field-item tokens can be nested in other tokens.

This means that with an entityreference field, I can link each item to the linked entity like this:

[node:field-my-reference-field:[field-item:delta]:url]

However, this feature is currently broken because the tokens are replaced in the wrong order. The field-item tokens are being added to the end of the $replace_tokens array, rather than the beginning.