Test with db without i18n

Problem/Motivation

For some time I've been wanting to run tests with a database that does not have i18n tables and columns. This has two new test fixutres, drupal6_no_i18n.php and drupal7_no_i18n.php, both made using the UI to uninstall all the i18n modules.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet