Make sure that the ID of the right revision is not less than the ID of the left revision

see #23497

git-svn-id: http://core.svn.wordpress.org/trunk@23832 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23833.

git-svn-id: http://core.svn.wordpress.org/trunk@23833 1a063a9b-81f0-0310-95a4-ce76da25c4cd