Kill unused foldOccSet
Kill unused foldOccSet

foldOccSet if used would be a potential source of nondeterminism.
Since it's not used we can just remove it.

vikraman/ghc,shlevy/ghc,sgillespie/ghc,vikraman/ghc,sgillespie/ghc,mettekou/ghc,sdiehl/ghc,mettekou/ghc,snoyberg/ghc,shlevy/ghc,snoyberg/ghc,snoyberg/ghc,mettekou/ghc,olsner/ghc,olsner/ghc,sgillespie/ghc,mettekou/ghc,vikraman/ghc,mettekou/ghc,sgillespie/ghc,mettekou/ghc,shlevy/ghc,olsner/ghc,sdiehl/ghc,olsner/ghc,sgillespie/ghc,ezyang/ghc,vTurbine/ghc,vTurbine/ghc,vikraman/ghc,snoyberg/ghc,snoyberg/ghc,ezyang/ghc,vTurbine/ghc,olsner/ghc,mettekou/ghc,ezyang/ghc,vTurbine/ghc,shlevy/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,vikraman/ghc,snoyberg/ghc,vikraman/ghc,sdiehl/ghc,ezyang/ghc,shlevy/ghc,shlevy/ghc,ezyang/ghc,vTurbine/ghc,vikraman/ghc,sgillespie/ghc,ezyang/ghc,sdiehl/ghc,olsner/ghc,vTurbine/ghc,ezyang/ghc,vTurbine/ghc,sgillespie/ghc,snoyberg/ghc,olsner/ghc