Media: add a new image size, medium_large. Bumps db version to add new options.

Adds unit tests.

Props DH-Shredder, joemcgill, azaozz.
Fixes #34196.

Built from https://develop.svn.wordpress.org/trunk@35479


git-svn-id: http://core.svn.wordpress.org/trunk@35443 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/schema.php

@@ -506,6 +506,10 @@ function populate_options() {
 	// 4.3.0
 	'finished_splitting_shared_terms' => 1,
 	'site_icon' => 0,
+
+	// 4.4.0
+	'medium_large_size_w' => 768,
+	'medium_large_size_h' => 0,
 	);
 
 	// 3.3