Tests: Skip `test_readme()` if the HTTP request to `secure.php.net` or `dev.mysql.com` failed on timeout.

Move `skipTestOnTimeout()` to `WP_UnitTestCase_Base` to avoid duplication.

Merges [46682] and [46996] to the 5.2 branch.
See #51669.
Built from https://develop.svn.wordpress.org/branches/5.2@50093


git-svn-id: http://core.svn.wordpress.org/branches/5.2@49787 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/blocks/rss.php

@@ -80,7 +80,7 @@ function render_block_core_rss( $attributes ) {
 	}
 
 	$classes           = 'grid' === $attributes['blockLayout'] ? ' is-grid columns-' . $attributes['columns'] : '';
-	$list_items_markup = sprintf( "<ul class='%s'>%s</ul>", esc_attr( $class ), $list_items );
+	$list_items_markup = sprintf( "<ul class='%s'>%s</ul>", esc_attr( $classes ), $list_items );
 
 	// PHP 5.2 compatibility. See: http://simplepie.org/wiki/faq/i_m_getting_memory_leaks.
 	$rss->__destruct();
@@ -93,7 +93,8 @@ function render_block_core_rss( $attributes ) {
  * Registers the `core/rss` block on server.
  */
 function register_block_core_rss() {
-	register_block_type( 'core/rss',
+	register_block_type(
+		'core/rss',
 		array(
 			'attributes'      => array(
 				'columns'        => array(