Display name fatal error if names are too long

This is kinda obscure but it's legit for the components of a display name to add up to more than the display name allows (128) char. 

For example

civicrm_api3('Contact', 'create', array(

  'first_name' => str_pad('a', 64, 'a'),

  'last_name' => str_pad('a', 64, 'a'),

));

will give a fatal error as 64 + 64 +1 (the space) is more than the number of chars allowed.

I don't think we should give a hard error on a calculated field being too long & believe a truncate is fine - ie 

if (strlen($contact->display_name) > 128) {
$contact->display_name = substr($contact->display_name, 128);
}
if (strlen($contact->sort_name) > 128) {
$contact->sort_name = substr($contact->sort_name, 128);
}