Tests: Replace most instances of wpmu_delete_blog() not specifically testing that function with wp_delete_site().

Follow-up to [47011].

See #47195.

git-svn-id: https://develop.svn.wordpress.org/trunk@47012 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/multisite/bootstrap.php

@@ -103,7 +103,7 @@ if ( is_multisite() ) :
 			global $wpdb;
 
 			foreach ( self::$site_ids as $id ) {
-				wpmu_delete_blog( $id, true );
+				wp_delete_site( $id );
 			}
 
 			foreach ( self::$network_ids as $id ) {