[GHC] #12871: Upgrade Mingw-w64 bindist for GHC to GCC 6.2.0 and Binutils 2.27.2

[GHC]

#12871: Upgrade Mingw-w64 bindist for GHC to GCC 6.2.0 and Binutils 2.27.2
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           Reporter:  Phyx-          |             Owner:
               Type:  task           |            Status:  new
           Priority:  normal         |         Milestone:  8.2.1
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):  Phab:D2749     |         Wiki Page:
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 Bump up the bindists to have a more up to date gcc and binutils.

 The updated binutils should fix LLVM backend on 64bit Windows.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12871>
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