Move cross-browser styled selects upstream

Despite the issue summary says Move styling into Seven. that is not what the patch does. it adds styles to Drupal core, since it alters Drupal core files, including the ones for a module that does not exist in Drupal 9 or higher releases. (I cannot find any outside_in module.)

I guess this issue can be considered outdated, but this should be verified by Drupal core maintainers.