Code Modernisation: Replace call_user_func_array() in various __call() methods with dynamic function calls.

The callback in these functions is always checked against a limited list of valid callbacks that can be safely changed to dynamic function calls.

Props jrf.
See #47678.

git-svn-id: https://develop.svn.wordpress.org/trunk@46144 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-xmlrpc-server.php

@@ -177,7 +177,7 @@ class wp_xmlrpc_server extends IXR_Server {
 	 */
 	public function __call( $name, $arguments ) {
 		if ( '_multisite_getUsersBlogs' === $name ) {
-			return call_user_func_array( array( $this, $name ), $arguments );
+			return $this->_multisite_getUsersBlogs( ...$arguments );
 		}
 		return false;
 	}