Of course that div is still present, since its html (an empty div) is still printed. But, again, with display:none it will make no volume, so will not push anything.
You changed a core file to achieve the same visual result, which is wrong, ’cause:
1) if you changed the file in customizr then you have to re-apply the change after each update
2) if you copied that file in your child-theme tree then, in future, you might miss some customizr improvements on that file.
Alternatively if you don’t want that div printed at all revert your changes and use this code in your child-theme functions.php:
add_action('wp_head', 'remove_social_in_header');
function remove_social_in_header(){
remove_action('__navbar', array(TC_header_main::$instance, 'tc_social_in_header'));
}
