[GHC] #3384: Add HsSyn prettyprinter tests

[GHC]

#3384: Add HsSyn prettyprinter tests
-------------------------------+--------------------------------------------
  Reporter:  igloo             |          Owner:                  
      Type:  task              |         Status:  new             
  Priority:  normal            |      Milestone:  _|_             
 Component:  Test Suite        |        Version:  6.10.4          
  Severity:  normal            |       Keywords:                  
Difficulty:  Unknown           |       Testcase:                  
        Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
-------------------------------+--------------------------------------------
 Add HsSyn prettyprinter tests. See #1966 for some discussion.

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