In #38586 the ability to parse arrays as csv was introduced, however it didn't add any support for validating csv arrays. This adds such sanitization, and also a good amount of unit tests for all sanitization baed off schema.
See #38586.
git-svn-id: https://develop.svn.wordpress.org/trunk@39061 602fd350-edb4-49c9-b593-d223f7449a82