When searching for users using the `search` arg in `get_users()`/`WP_User_Query`, also search the user's email, url, and display name.

Adds unit tests.

Props mordauk, wonderboymusic.
Fixes #27304.

Built from https://develop.svn.wordpress.org/trunk@32980


git-svn-id: http://core.svn.wordpress.org/trunk@32951 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/user.php

@@ -797,7 +797,7 @@ class WP_User_Query {
 				elseif ( preg_match('|^https?://|', $search) && ! ( is_multisite() && wp_is_large_network( 'users' ) ) )
 					$search_columns = array('user_url');
 				else
-					$search_columns = array('user_login', 'user_nicename');
+					$search_columns = array('user_login', 'user_url', 'user_email', 'user_nicename', 'display_name');
 			}
 
 			/**

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-alpha-32979';
+$wp_version = '4.3-alpha-32980';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.