$messageTokens has two formats in use

Identified this while debugging CRM-19757, but having pursued the suggestion of an additional method to reformat the passed $messageTokens array, I found that it did not address the issue at hand there.

May relate to: CRM-18713, CRM-19757.

Here's an addition to TokenCompatSubscriber which reformats $messageTokens into the CiviMail-style format. IMO the numerically keyed array format is superior, but I wrote this to see if the reformat would fix an issue affecting scheduled actions. It didn't, so this is not a PR.

• https://github.com/xurizaemon/civicrm-core/commit/90539237365ec9ebf36b703116108d50ac79135c

I identified this behaviour while debugging token support in scheduled reminders (action_schedule). I found that testing CiviMail and ActionSchedule one after the other, a different $messageTokens value was passed into TokenCompatSubscriber::onEvaluate()

Coming from CiviMail:

    [ 'contact' => [ 'first_name' => 1, 'email_greeting' => 1 ] ] ]

Coming from ActionSchedule:

    [ 'contact' => [ 'checksum', 'contact_id' ] ]