Build/Test Tools: Support Docker compose override files.

This updates the logic introduced in [59279] to account for the presence of `docker-compose.override.yml` files.

Reviewed by peterwilsoncc.
Merges 59283] to the 6.7 branch.

Props xknown, davidbaumwald.
See #61218.
Built from https://develop.svn.wordpress.org/branches/6.7@59311


git-svn-id: http://core.svn.wordpress.org/branches/6.7@58697 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-RC1-59310';
+$wp_version = '6.7-RC1-59311';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.