[NFC] Correct selector conflict sorting rules
[NFC] Correct selector conflict sorting rules

When two members have the same ObjC selector, there’s a test used to make sure that we’re “giving” the selector to the more “authoritative” of the two. However, its logic is not symmetrical, which I suspect could cause misbehavior in some edge cases. This change formalizes the logic in a way that eliminates the asymmetry.

ahoppen/swift,apple/swift,ahoppen/swift,glessard/swift,atrick/swift,benlangmuir/swift,benlangmuir/swift,JGiola/swift,apple/swift,hooman/swift,roambotics/swift,glessard/swift,parkera/swift,benlangmuir/swift,ahoppen/swift,tkremenek/swift,rudkx/swift,roambotics/swift,roambotics/swift,ahoppen/swift,xwu/swift,benlangmuir/swift,gregomni/swift,parkera/swift,benlangmuir/swift,roambotics/swift,glessard/swift,parkera/swift,roambotics/swift,tkremenek/swift,apple/swift,tkremenek/swift,glessard/swift,gregomni/swift,JGiola/swift,atrick/swift,hooman/swift,JGiola/swift,apple/swift,parkera/swift,atrick/swift,hooman/swift,atrick/swift,rudkx/swift,xwu/swift,rudkx/swift,xwu/swift,tkremenek/swift,parkera/swift,xwu/swift,JGiola/swift,xwu/swift,hooman/swift,glessard/swift,JGiola/swift,xwu/swift,glessard/swift,parkera/swift,ahoppen/swift,atrick/swift,parkera/swift,atrick/swift,ahoppen/swift,JGiola/swift,tkremenek/swift,gregomni/swift,hooman/swift,tkremenek/swift,rudkx/swift,benlangmuir/swift,roambotics/swift,gregomni/swift,xwu/swift,gregomni/swift,parkera/swift,rudkx/swift,apple/swift,apple/swift,hooman/swift,tkremenek/swift,hooman/swift,rudkx/swift,gregomni/swift