Clean out old mailbox names logic and fix a couple of bugs.

* Get rid of old Account.getxxxFolderName() calls.
* Clean up any call sites to them
* Properly rename the existing special folder name identifiers
* Use a hash table in MessagingController to improve identification
    of special folders for IMAP accounts
* Fix a bug in Controller, which was creating new server-side folders
    using localized names.
* Fix a bunch of code in Controller that was using mContext, instead of
    using mProviderContext to support testability.
* Fix broken unit tests in ControllerProviderOpsTests

Fixes bug 1904373
1 file changed