Testsuite: diff non-whitespace normalised output (#10152)
Testsuite: diff non-whitespace normalised output (#10152)

On a test failure, we show a diff between the expected and the actual
output. The method of how we do this has changed a couple of times:

* In 2007: 9951189ccf90b709436fa55ee49eeef031f79f4e
  "On failure, diff the normalised test outputs"

* In 2011: 3019b1e409c129ef7af63e6a7408fb36ec44444b
  "When the output files differ, present the diffs between the *actual*
  output, not the normalised output. The latter may have newlines
  removed, making the diff unreadable."

* In 2015 (now): do something in between.
  - Do apply the normalisers again, to make the diff smaller (only
    showing the actual problem).
  - But don't apply normalise_whitespace, as it indeed makes the diff
    unreadable.

Differential Revision: https://phabricator.haskell.org/D984

acowley/ghc,elieux/ghc,AlexanderPankiv/ghc,olsner/ghc,sdiehl/ghc,AlexanderPankiv/ghc,gridaphobe/ghc,da-x/ghc,da-x/ghc,elieux/ghc,anton-dessiatov/ghc,da-x/ghc,da-x/ghc,vikraman/ghc,shlevy/ghc,mettekou/ghc,gridaphobe/ghc,vikraman/ghc,AlexanderPankiv/ghc,elieux/ghc,AlexanderPankiv/ghc,sgillespie/ghc,wxwxwwxxx/ghc,ml9951/ghc,sgillespie/ghc,sgillespie/ghc,nkaretnikov/ghc,ezyang/ghc,da-x/ghc,oldmanmike/ghc,anton-dessiatov/ghc,mfine/ghc,vikraman/ghc,oldmanmike/ghc,mettekou/ghc,vTurbine/ghc,gridaphobe/ghc,mettekou/ghc,mcschroeder/ghc,ml9951/ghc,TomMD/ghc,olsner/ghc,snoyberg/ghc,urbanslug/ghc,mfine/ghc,wxwxwwxxx/ghc,wxwxwwxxx/ghc,siddhanathan/ghc,vikraman/ghc,vTurbine/ghc,tjakway/ghcjvm,gridaphobe/ghc,ml9951/ghc,ghc-android/ghc,vTurbine/ghc,mcschroeder/ghc,GaloisInc/halvm-ghc,nkaretnikov/ghc,sdiehl/ghc,snoyberg/ghc,TomMD/ghc,vTurbine/ghc,nushio3/ghc,da-x/ghc,snoyberg/ghc,TomMD/ghc,sdiehl/ghc,oldmanmike/ghc,oldmanmike/ghc,nkaretnikov/ghc,TomMD/ghc,GaloisInc/halvm-ghc,shlevy/ghc,sdiehl/ghc,vTurbine/ghc,vikraman/ghc,mcschroeder/ghc,anton-dessiatov/ghc,wxwxwwxxx/ghc,tjakway/ghcjvm,olsner/ghc,shlevy/ghc,anton-dessiatov/ghc,ghc-android/ghc,anton-dessiatov/ghc,tjakway/ghcjvm,urbanslug/ghc,siddhanathan/ghc,acowley/ghc,urbanslug/ghc,ml9951/ghc,mettekou/ghc,TomMD/ghc,olsner/ghc,TomMD/ghc,nkaretnikov/ghc,olsner/ghc,snoyberg/ghc,anton-dessiatov/ghc,acowley/ghc,mcschroeder/ghc,snoyberg/ghc,oldmanmike/ghc,ml9951/ghc,snoyberg/ghc,GaloisInc/halvm-ghc,ghc-android/ghc,siddhanathan/ghc,sgillespie/ghc,elieux/ghc,wxwxwwxxx/ghc,tjakway/ghcjvm,nkaretnikov/ghc,ezyang/ghc,shlevy/ghc,ghc-android/ghc,acowley/ghc,AlexanderPankiv/ghc,da-x/ghc,elieux/ghc,shlevy/ghc,AlexanderPankiv/ghc,urbanslug/ghc,nushio3/ghc,shlevy/ghc,ezyang/ghc,sgillespie/ghc,GaloisInc/halvm-ghc,wxwxwwxxx/ghc,gridaphobe/ghc,nushio3/ghc,nushio3/ghc,tjakway/ghcjvm,olsner/ghc,oldmanmike/ghc,gridaphobe/ghc,GaloisInc/halvm-ghc,olsner/ghc,mfine/ghc,anton-dessiatov/ghc,siddhanathan/ghc,mcschroeder/ghc,ml9951/ghc,vTurbine/ghc,ezyang/ghc,GaloisInc/halvm-ghc,AlexanderPankiv/ghc,mfine/ghc,sgillespie/ghc,urbanslug/ghc,sgillespie/ghc,elieux/ghc,ghc-android/ghc,sdiehl/ghc,siddhanathan/ghc,mfine/ghc,urbanslug/ghc,elieux/ghc,snoyberg/ghc,ml9951/ghc,nkaretnikov/ghc,oldmanmike/ghc,nushio3/ghc,vikraman/ghc,siddhanathan/ghc,ghc-android/ghc,acowley/ghc,tjakway/ghcjvm,ezyang/ghc,shlevy/ghc,vikraman/ghc,mettekou/ghc,nushio3/ghc,tjakway/ghcjvm,mettekou/ghc,gridaphobe/ghc,sdiehl/ghc,urbanslug/ghc,vTurbine/ghc,ezyang/ghc,mettekou/ghc,ezyang/ghc,sdiehl/ghc,mcschroeder/ghc,nushio3/ghc,nkaretnikov/ghc,ml9951/ghc,wxwxwwxxx/ghc,mfine/ghc,siddhanathan/ghc,acowley/ghc,TomMD/ghc,acowley/ghc,ghc-android/ghc,mcschroeder/ghc,mfine/ghc,GaloisInc/halvm-ghc