The rewrite functions have all kinds of cross-dependencies (like `WP_Query`), so loading the file by itself would have been bizarre (and still is).
Creates:
`rewrite-constants.php`
`rewrite-functions.php`
`class-wp-rewrite.php`
`rewrite.php` contains only top-level code. Class file only contains the class. Functions file only contains functions.
See #33413.
git-svn-id: https://develop.svn.wordpress.org/trunk@33751 602fd350-edb4-49c9-b593-d223f7449a82