WP_Query: always convert `any` post type values to public values.

[peterwilsoncc]

Instantiating a WP_Query with each of the following parameters will return all public post types (post, pages and attachments by default):

<?php
new WP_Query( [ 'post_type' => 'any' ] );
new WP_Query( [ 'post_type' => [ 'any' ] ] );
/*
WHERE 1=1
  AND wp_posts.post_type IN ('post', 'page', 'attachment')
  AND ((wp_posts.post_status <> 'trash' AND wp_posts.post_status <> 'auto-draft'))
 */

However, manually adding another post type to an array containing any will result in a query searching for the post types any and the subsequent post types. This is the case regardless as to whether the included types are public or private.

<?php
new WP_Query( [ 'post_type' => [ 'any', 'post' ] ] );
/*
WHERE 1=1 
  AND wp_posts.post_type IN ('any', 'post')
  AND ((wp_posts.post_status <> 'trash' AND wp_posts.post_status <> 'auto-draft'))
*/

new WP_Query( [ 'post_type' => [ 'any', 'revision' ] ] );
/*
WHERE 1=1 
  AND wp_posts.post_type IN ('any', 'revision')
  AND ((wp_posts.post_status <> 'trash' AND wp_posts.post_status <> 'auto-draft'))
*/

I am writing up some basic tests and create a pull request on GH to demonstrate the unexpected queries.

https://core.trac.wordpress.org/ticket/52167