HTML API: Test code improvements in virtual node breadcrumb tests.

Follow-up after feedback to newly-introduced tests,
mostly to enhance the message when the tests fail.

Developed in WordPress/wordpress-develop#7030
Discussed in https://core.trac.wordpress.org/ticket/61646

Follow-up to [58592].

Props dmsnell, jonsurrell.
See #61646.

Built from https://develop.svn.wordpress.org/trunk@58741


git-svn-id: https://core.svn.wordpress.org/trunk@58143 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-alpha-58740';
+$wp_version = '6.7-alpha-58741';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.