Editor: add sanity limit for editor height of 5000px, save only when resizing ...

Editor: add sanity limit for editor height of 5000px, save only when resizing  the Visual or the Text editor, fixes #22708

git-svn-id: https://core.svn.wordpress.org/trunk@23016 1a063a9b-81f0-0310-95a4-ce76da25c4cd