If we set 'Surename + First name' in Administration > Security > Site policies > Full Name Format (fullnamedisplay), a course Participants list shows users as below. And if we use Japanese language (we use Surename + First name in Japan) and set 'language' in Full Name Format (fullnamedisplay), our Surename will be displayed under 'First name' label too.

First name / Surname
---------------------
Dougiamas Martin
Yoshida Mitsuhiro

Now 'Administration > Users > Accounts > Browse list of users' listing shows correctly as a setting of Full Name Format (fullnamedisplay).
So we need to fix lib/tablelib.php as below based on admin/user.php.

file: lib/tablelib.php
line: 661

[before]
$this->headers[$index] = '<a href="'.$this->baseurl.$this->request[TABLE_VAR_SORT].'=firstname">'.get_string('firstname').get_accesshide(get_string('sortby').' '.get_string('firstname').' '.$fsortorder).'</a> '.$icon_sort_first.' / '.
'<a href="'.$this->baseurl.$this->request[TABLE_VAR_SORT].'=lastname">'.get_string('lastname').get_accesshide(get_string('sortby').' '.get_string('lastname').' '.$lsortorder).'</a> '.$icon_sort_last;

[after]
if (($CFG->fullnamedisplay == 'firstname lastname') or
($CFG->fullnamedisplay == 'firstname') or
($CFG->fullnamedisplay == 'language' and $fullnamelanguage == 'firstname lastname' )) {
$this->headers[$index] = '<a href="'.$this->baseurl.$this->request[TABLE_VAR_SORT].'=firstname">'.get_string('firstname').get_accesshide(get_string('sortby').' '.get_string('firstname').' '.$fsortorder).'</a> '.$icon_sort_first.' / '.
'<a href="'.$this->baseurl.$this->request[TABLE_VAR_SORT].'=lastname">'.get_string('lastname').get_accesshide(get_string('sortby').' '.get_string('lastname').' '.$lsortorder).'</a> '.$icon_sort_last;
} else { // ($CFG->fullnamedisplay == 'language' and $fullnamelanguage == 'lastname firstname')
($CFG->fullnamedisplay == 'firstname') or
($CFG->fullnamedisplay == 'language' and $fullnamelanguage == 'firstname lastname' ))

{ $this->headers[$index] = '<a href="'.$this->baseurl.$this->request[TABLE_VAR_SORT].'=lastname">'.get_string('lastname').get_accesshide(get_string('sortby').' '.get_string('lastname').' '.$lsortorder).'</a> '.$icon_sort_last.' / '. '<a href="'.$this->baseurl.$this->request[TABLE_VAR_SORT].'=firstname">'.get_string('firstname').get_accesshide(get_string('sortby').' '.get_string('firstname').' '.$fsortorder).'</a> '.$icon_sort_first; }

1. Please see the attachment 'tablelib.php.patch' for more details.