[GHC] #13535: vector test suite uses excessive memory on GHC 8.2

[GHC]

#13535: vector test suite uses excessive memory on GHC 8.2
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  bgamari
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #10800            |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by dfeuer):

 I cut down the test case some more, to `Smaller-Vector.hs`, with desugar
 dump in `smaller-ds.diff`. The relative performance contrast isn't
 ''quite'' as strong, but it's still almost five times as bad in HEAD as
 before the badness started.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13535#comment:34>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler