Tests: Add hook priority call order tests.

Adds happy (integer) and unhappy (non-integer) tests for validating the priority call order for:

* `do_action()`
* `WP_Hook::do_action()`
* `apply_filters()`
* `WP_Hook::apply_filters()`

As each of these functions have differing code, the tests are added to each to ensure expected results and protect against future regressions.

Follow-up to [53804], [52010], [25002], [25/tests], [62/tests].

Props hellofromTonya, mukesh27, dd32, valendesigns, drrobotnik.
Fixes #60193.
Built from https://develop.svn.wordpress.org/trunk@57257


git-svn-id: http://core.svn.wordpress.org/trunk@56763 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-alpha-57256';
+$wp_version = '6.5-alpha-57257';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.