Summary: Added flag -fwarn-unticked-promoted-constructors

Test Plan: test T9778 under tests/rename/should_compile

Reviewers: jstolarek, simonpj, austin

Reviewed By: jstolarek, simonpj, austin

Subscribers: simonpj, goldfire, jstolarek, thomie, carter

Differential Revision: https://phabricator.haskell.org/D534

GHC Trac Issues: #9778