Ensure recently converted groups cache matches previous behabiour my …

…setting withArray as fast for it

Ensure custom data cache use the fastArray Cache

Civi/Core/Container.php

@@ -168,7 +168,7 @@ public function createContainer() {
       // For Caches that we don't really care about the ttl for and/or maybe accessed
       // fairly often we use the fastArrayDecorator which improves reads and writes, these
       // caches should also not have concurrency risk.
-      $fastArrayCaches = ['groups', 'navigation'];
+      $fastArrayCaches = ['groups', 'navigation', 'customData'];
       if (in_array($cacheSvc, $fastArrayCaches)) {
         $definitionParams['withArray'] = 'fast';
       }