Build/Test Tools: Standardise the name, signature, and usage of the wpSetUpBeforeClass() method that's used in test classes.

This brings consistency to this often-used method, and allows IDEs to provide help to developers when using its `$factory` parameter.

See #51344


git-svn-id: https://develop.svn.wordpress.org/trunk@49603 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/rest-api/rest-block-renderer-controller.php

@@ -98,7 +98,7 @@ class REST_Block_Renderer_Controller_Test extends WP_Test_REST_Controller_Testca
 	 *
 	 * @param WP_UnitTest_Factory $factory Helper that lets us create fake data.
 	 */
-	public static function wpSetUpBeforeClass( $factory ) {
+	public static function wpSetUpBeforeClass( WP_UnitTest_Factory $factory ) {
 		self::$user_id = $factory->user->create(
 			array(
 				'role' => 'editor',