RequirementMachine: The three RewriteSystem::simplify*() methods check flags independently
RequirementMachine: The three RewriteSystem::simplify*() methods check flags independently

We used to skip a pass if any of the three flags were set, but we have
to check them separately to ensure that all flags are independently
set correctly.

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