[39048] added CSV support to array types, this change explicitly parses term lists as IDs, and adds tests. Props timmydcrawford, pento. Fixes #38553. Built from https://develop.svn.wordpress.org/trunk@39055 git-svn-id: http://core.svn.wordpress.org/trunk@38997 1a063a9b-81f0-0310-95a4-ce76da25c4cd