Editor:
- Add CSS reset for the TinyMCE fullscreen mode when used on the Edit Post screen.
- Fix loading of the old and new DFW buttons, use another arg. passed to WP_Editors.
- Reset editor-expand when exiting TinyMCE fullscreen mode.
Fixes #30453.

git-svn-id: https://develop.svn.wordpress.org/trunk@30573 602fd350-edb4-49c9-b593-d223f7449a82