Event Registration with email only in a multi-language environment doesn't populate the sort_name / display_name fields

If an anonymous user registers for an event where only the emall address is collected - we create the contact but don't write the email address to display_name and sort_name columns as we should.

To recreate:

• configure multi-site w/ 2 languages
• go to event reg as anonymous for an event that allows pay-later and check that option (event 1 in sample data has this by default)
• complete the registration
• now check the contact table - both display_name and both sort_name columns are NULL

If you repeat this - but add a Profile that has first name and last name fields in it - then the contact fields ARE populated properly. Note that Email only is a bit of special case because the code has to "know" to push it into the name fields. However, since this is default behavior for these forms (no profile) - it could cause some problems / confusion.

NOTE: Pretty sure the same problem will occur w/ Online Contribution form submit.