Membership tokens not evaluated when used in Scheduled Reminder for membership entity

Membership tokens are not evaluated.

The fixes in Utils/Token.php contained in this PR fix the membership tokens issue. HOWEVER, those changes cause hundreds of regressions, hence closed that PR. We'll need to revisit the correct fix, making sure to test the greetingToken functionality and review the PR test build.

Here's an example of one of the regressions
https://test.civicrm.org/job/CiviCRM-Core-PR/767/testReport/junit/%28root%29/api_v3_ActivityContactTest/testCreateActivityContact/

Details:
I used two membership tokens in my scheduled reminder email

,

... and they are NOT being evaluated (they show up as empty in the output):
---- reminder output ----
Dear ,

Your :: :: (s/b membership type) membership expires on ::
:: (s/b end date).