[TypeChecker] NFC: Remove unused `DC` variable from `checkInheritanceClause`
[TypeChecker] NFC: Remove unused `DC` variable from `checkInheritanceClause`

gregomni/swift,gregomni/swift,ahoppen/swift,ahoppen/swift,ahoppen/swift,apple/swift,atrick/swift,rudkx/swift,JGiola/swift,benlangmuir/swift,benlangmuir/swift,rudkx/swift,benlangmuir/swift,gregomni/swift,glessard/swift,ahoppen/swift,ahoppen/swift,atrick/swift,glessard/swift,gregomni/swift,rudkx/swift,apple/swift,glessard/swift,rudkx/swift,glessard/swift,apple/swift,glessard/swift,roambotics/swift,glessard/swift,JGiola/swift,atrick/swift,JGiola/swift,JGiola/swift,atrick/swift,roambotics/swift,JGiola/swift,apple/swift,roambotics/swift,JGiola/swift,ahoppen/swift,benlangmuir/swift,gregomni/swift,roambotics/swift,atrick/swift,rudkx/swift,rudkx/swift,roambotics/swift,benlangmuir/swift,apple/swift,roambotics/swift,gregomni/swift,atrick/swift,apple/swift,benlangmuir/swift