[GHC] #3384: Add HsSyn prettyprinter tests

[GHC]

#3384: Add HsSyn prettyprinter tests
-------------------------------------+-------------------------------------
        Reporter:  igloo             |                Owner:
            Type:  task              |               Status:  patch
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Test Suite        |              Version:
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2752
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by alanz):

 This is passing all its tests on phab now, please review.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3384#comment:16>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler