Add a note why tcGetInstEnvs is duplicated.
Add a note why tcGetInstEnvs is duplicated.

Signed-off-by: Edward Z. Yang <dbd597f5635f432486c5d365e9bb585b3eaa1853@cs.stanford.edu>

AlexanderPankiv/ghc,tjakway/ghcjvm,urbanslug/ghc,nushio3/ghc,vikraman/ghc,olsner/ghc,jstolarek/ghc,ml9951/ghc,forked-upstream-packages-for-ghcjs/ghc,da-x/ghc,TomMD/ghc,nathyong/microghc-ghc,AlexanderPankiv/ghc,GaloisInc/halvm-ghc,ghc-android/ghc,da-x/ghc,mfine/ghc,mettekou/ghc,gridaphobe/ghc,elieux/ghc,siddhanathan/ghc,sgillespie/ghc,ezyang/ghc,gridaphobe/ghc,mfine/ghc,bitemyapp/ghc,anton-dessiatov/ghc,urbanslug/ghc,siddhanathan/ghc,acowley/ghc,ezyang/ghc,wxwxwwxxx/ghc,anton-dessiatov/ghc,sdiehl/ghc,nushio3/ghc,forked-upstream-packages-for-ghcjs/ghc,mfine/ghc,gcampax/ghc,ml9951/ghc,vTurbine/ghc,oldmanmike/ghc,tjakway/ghcjvm,ezyang/ghc,da-x/ghc,nushio3/ghc,wxwxwwxxx/ghc,shlevy/ghc,green-haskell/ghc,nkaretnikov/ghc,olsner/ghc,ml9951/ghc,shlevy/ghc,nushio3/ghc,gridaphobe/ghc,mettekou/ghc,olsner/ghc,wxwxwwxxx/ghc,nkaretnikov/ghc,christiaanb/ghc,acowley/ghc,bitemyapp/ghc,nathyong/microghc-ghc,vikraman/ghc,ml9951/ghc,gcampax/ghc,TomMD/ghc,urbanslug/ghc,vTurbine/ghc,gcampax/ghc,olsner/ghc,olsner/ghc,christiaanb/ghc,ghc-android/ghc,AlexanderPankiv/ghc,acowley/ghc,sgillespie/ghc,tjakway/ghcjvm,snoyberg/ghc,nathyong/microghc-ghc,mcschroeder/ghc,mcschroeder/ghc,mettekou/ghc,ghc-android/ghc,forked-upstream-packages-for-ghcjs/ghc,jstolarek/ghc,nkaretnikov/ghc,christiaanb/ghc,gcampax/ghc,mettekou/ghc,bitemyapp/ghc,nushio3/ghc,oldmanmike/ghc,oldmanmike/ghc,oldmanmike/ghc,nkaretnikov/ghc,nathyong/microghc-ghc,mfine/ghc,tjakway/ghcjvm,christiaanb/ghc,ghc-android/ghc,ml9951/ghc,gridaphobe/ghc,siddhanathan/ghc,GaloisInc/halvm-ghc,forked-upstream-packages-for-ghcjs/ghc,da-x/ghc,urbanslug/ghc,bitemyapp/ghc,vTurbine/ghc,shlevy/ghc,AlexanderPankiv/ghc,mcschroeder/ghc,anton-dessiatov/ghc,fmthoma/ghc,sdiehl/ghc,TomMD/ghc,snoyberg/ghc,oldmanmike/ghc,ezyang/ghc,forked-upstream-packages-for-ghcjs/ghc,acowley/ghc,fmthoma/ghc,nushio3/ghc,tjakway/ghcjvm,vikraman/ghc,acowley/ghc,mcschroeder/ghc,shlevy/ghc,mfine/ghc,mcschroeder/ghc,mfine/ghc,olsner/ghc,anton-dessiatov/ghc,vikraman/ghc,fmthoma/ghc,GaloisInc/halvm-ghc,da-x/ghc,shlevy/ghc,sgillespie/ghc,vTurbine/ghc,nathyong/microghc-ghc,snoyberg/ghc,gridaphobe/ghc,tjakway/ghcjvm,jstolarek/ghc,ezyang/ghc,elieux/ghc,vikraman/ghc,mettekou/ghc,wxwxwwxxx/ghc,mfine/ghc,TomMD/ghc,green-haskell/ghc,green-haskell/ghc,fmthoma/ghc,fmthoma/ghc,mcschroeder/ghc,mcschroeder/ghc,vTurbine/ghc,wxwxwwxxx/ghc,da-x/ghc,sgillespie/ghc,nushio3/ghc,ezyang/ghc,siddhanathan/ghc,elieux/ghc,GaloisInc/halvm-ghc,ml9951/ghc,ezyang/ghc,oldmanmike/ghc,christiaanb/ghc,gridaphobe/ghc,snoyberg/ghc,wxwxwwxxx/ghc,TomMD/ghc,shlevy/ghc,christiaanb/ghc,siddhanathan/ghc,snoyberg/ghc,mettekou/ghc,nathyong/microghc-ghc,sdiehl/ghc,ml9951/ghc,acowley/ghc,da-x/ghc,fmthoma/ghc,AlexanderPankiv/ghc,GaloisInc/halvm-ghc,gcampax/ghc,mettekou/ghc,elieux/ghc,ml9951/ghc,TomMD/ghc,acowley/ghc,vikraman/ghc,gcampax/ghc,ghc-android/ghc,sgillespie/ghc,GaloisInc/halvm-ghc,nkaretnikov/ghc,sdiehl/ghc,vTurbine/ghc,AlexanderPankiv/ghc,vikraman/ghc,christiaanb/ghc,nkaretnikov/ghc,urbanslug/ghc,TomMD/ghc,siddhanathan/ghc,ghc-android/ghc,elieux/ghc,olsner/ghc,sdiehl/ghc,sdiehl/ghc,fmthoma/ghc,anton-dessiatov/ghc,forked-upstream-packages-for-ghcjs/ghc,anton-dessiatov/ghc,shlevy/ghc,ghc-android/ghc,green-haskell/ghc,nathyong/microghc-ghc,green-haskell/ghc,gcampax/ghc,urbanslug/ghc,wxwxwwxxx/ghc,oldmanmike/ghc,snoyberg/ghc,tjakway/ghcjvm,bitemyapp/ghc,jstolarek/ghc,vTurbine/ghc,forked-upstream-packages-for-ghcjs/ghc,AlexanderPankiv/ghc,snoyberg/ghc,elieux/ghc,urbanslug/ghc,sgillespie/ghc,anton-dessiatov/ghc,jstolarek/ghc,siddhanathan/ghc,sgillespie/ghc,gridaphobe/ghc,sdiehl/ghc,GaloisInc/halvm-ghc,nkaretnikov/ghc,elieux/ghc