Build/Test Tools: Alias the Getopt class conditionally, as the clas…

…s no longer exists in PHPUnit 9.x.

Most of the aliasing in this `compat.php` file is redundant as PHPUnit 5.7.21+ contains a forward compatibility layer for these classes anyway (= PHPUnit provides both the namespaced and underscore named versions of these classes in PHPUnit 5.7.21+).

All the same, the file and the aliases are left in place for the time being, as plugins/themes using the WP test suite as the basis for their integration tests may rely on it, though WP itself should not really need it anymore, save for maybe one or two classes.

Follow-up to [51559-51569].

Props jrf.
See #46149.
Built from https://develop.svn.wordpress.org/trunk@51570


git-svn-id: http://core.svn.wordpress.org/trunk@51181 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51569';
+$wp_version = '5.9-alpha-51570';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.