Tests: Synchronize Theme.JSON unit test between Core and Gutenberg.

Merges the changes from Core and Gutenberg for the following tests:

- WP_REST_Global_Styles_Controller_Test
- Tests_Theme_wpThemeJsonResolver
- Tests_Theme_wpThemeJsonSchema
- Tests_Theme_wpThemeJson

This will help ensure the stability of the theme.json style generation.

Props ajlende, scruffian, aaronrobertshaw, get_dave, youknowriad.
Fixes #60387.
Built from https://develop.svn.wordpress.org/trunk@57662


git-svn-id: http://core.svn.wordpress.org/trunk@57163 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-beta1-57661';
+$wp_version = '6.5-beta1-57662';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.