WANObjectCache: Change getWithSetCallback() signature to key/ttl/callback/opts
- Put 'checkKeys' param in opts array instead of as a separate parameter. It's neat to not have to skip unnamed/positional arguments that are optional.
- Move TTL to be before callback instead of after. This avoids dangling integers toward the bottom of a large code block that have no obvious meaning. Matches BagOStuff::getWithSetCallback.
Add unit test for lockTSE to confirm
(cherry picked from commit 09cbebb22439bf4223e87ceb3e42169dc85fd311)