Prevent large images in comments from overflowing the meta box.

props mattheu.
fixes #26643.
Built from https://develop.svn.wordpress.org/trunk@27252


git-svn-id: http://core.svn.wordpress.org/trunk@27109 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Force UTF-8 in load-styles.php, like we do in load-scripts.php.

props iamfriendly, mjbanks.
fixes #25012.
Built from https://develop.svn.wordpress.org/trunk@27253


git-svn-id: http://core.svn.wordpress.org/trunk@27110 1a063a9b-81f0-0310-95a4-ce76da25c4cd