Load: No-op `locale.php`

After re-adding `locale.php` in [39455], remove the content of the file so that it can't cause errors in the event of something loading it early in the WordPress load process.

See #39027.


Built from https://develop.svn.wordpress.org/trunk@39456


git-svn-id: https://core.svn.wordpress.org/trunk@39396 1a063a9b-81f0-0310-95a4-ce76da25c4cd