Restore the bottom border to .wp-editor-container so it's not missing when the editor appears outside the main editor container. Fixes #26241, props mattheu.
Built from https://develop.svn.wordpress.org/trunk@26410


git-svn-id: http://core.svn.wordpress.org/trunk@26310 1a063a9b-81f0-0310-95a4-ce76da25c4cd