email tests do not properly replace tokens

There are two problems in the test email code:

First, the test is not case-sensitive. So, if you enter Jamie@email.org and there is a matching contact with the email address jamie@email.org, a new contact will be created instead of using the existing contact.

To add to the confusion, if you delete the duplicate contact, the test mailing code might still email to this contact because the search doesn't restrict to contacts that have is_deleted set to 0.