Query: Ensure that sticky post query returns all sticky posts.

Ensure that the `posts_per_page` parameter submit to sticky post query matches the number of sticky posts requested. 

Follow-up to [52982]

Props Spacedmonkey, peterwilsoncc.
See #36907.



git-svn-id: https://develop.svn.wordpress.org/trunk@52990 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-query.php

@@ -3263,6 +3263,7 @@ class WP_Query {
 						'post__in'               => $sticky_posts,
 						'post_type'              => $post_type,
 						'post_status'            => 'publish',
+						'posts_per_page'         => count( $sticky_posts ),
 						'suppress_filters'       => $q['suppress_filters'],
 						'cache_results'          => $q['cache_results'],
 						'update_post_meta_cache' => $q['update_post_meta_cache'],