Serialize on the server the paths of derived state closures accessed during directive processing and include them in the serialized data. During the Interactivity API hydration, if a directive reads one of those paths before its JavaScript getter is available, keep the server-rendered value intact instead of replacing it with `undefined`. props darerodz. Fixes #63898. Built from https://develop.svn.wordpress.org/trunk@60953 git-svn-id: http://core.svn.wordpress.org/trunk@60289 1a063a9b-81f0-0310-95a4-ce76da25c4cd