Wrong join added to the query when i18n is enabled

Here's how to reproduce the problem:

Create a views_calc field with %node.nid as its value.
Create a node view with the views_calc field that you created.
The following query is generated:

Now enable the core "content translation" module. The generated query is now:

What happens is that when the content translation module is enabled, the join data from translation.views.inc is used and you end up with a gazillion rows because of the extra join.

This is most likely a bug in views and would appear in any module that tries to do a $query->add_table('node') twice with the content translation module enabled, but I'm posting it here since it really appears in a views_calc context.