Assert when we expect to resolve a callee overload
Assert when we expect to resolve a callee overload

This helps ensure we don't miss cases where `getChoiceFor` was meant to
return a callee overload but doesn't.

tkremenek/swift,jmgc/swift,tkremenek/swift,atrick/swift,JGiola/swift,jckarter/swift,devincoughlin/swift,sschiau/swift,gregomni/swift,karwa/swift,gribozavr/swift,hooman/swift,jmgc/swift,harlanhaskins/swift,airspeedswift/swift,apple/swift,nathawes/swift,gregomni/swift,glessard/swift,lorentey/swift,jmgc/swift,aschwaighofer/swift,gregomni/swift,allevato/swift,allevato/swift,ahoppen/swift,xwu/swift,benlangmuir/swift,parkera/swift,atrick/swift,xwu/swift,xwu/swift,glessard/swift,aschwaighofer/swift,harlanhaskins/swift,lorentey/swift,parkera/swift,glessard/swift,xwu/swift,shahmishal/swift,atrick/swift,airspeedswift/swift,gribozavr/swift,parkera/swift,nathawes/swift,CodaFi/swift,sschiau/swift,rudkx/swift,nathawes/swift,sschiau/swift,lorentey/swift,gribozavr/swift,roambotics/swift,parkera/swift,stephentyrone/swift,gribozavr/swift,karwa/swift,glessard/swift,ahoppen/swift,jckarter/swift,karwa/swift,allevato/swift,harlanhaskins/swift,allevato/swift,JGiola/swift,tkremenek/swift,apple/swift,sschiau/swift,rudkx/swift,stephentyrone/swift,harlanhaskins/swift,lorentey/swift,tkremenek/swift,benlangmuir/swift,rudkx/swift,aschwaighofer/swift,stephentyrone/swift,harlanhaskins/swift,gribozavr/swift,hooman/swift,jmgc/swift,hooman/swift,atrick/swift,shahmishal/swift,xwu/swift,glessard/swift,CodaFi/swift,CodaFi/swift,devincoughlin/swift,apple/swift,stephentyrone/swift,hooman/swift,apple/swift,gregomni/swift,JGiola/swift,glessard/swift,jmgc/swift,atrick/swift,CodaFi/swift,tkremenek/swift,roambotics/swift,JGiola/swift,aschwaighofer/swift,ahoppen/swift,devincoughlin/swift,shahmishal/swift,airspeedswift/swift,airspeedswift/swift,devincoughlin/swift,harlanhaskins/swift,atrick/swift,CodaFi/swift,rudkx/swift,ahoppen/swift,xwu/swift,CodaFi/swift,jckarter/swift,gribozavr/swift,allevato/swift,rudkx/swift,nathawes/swift,nathawes/swift,shahmishal/swift,sschiau/swift,tkremenek/swift,hooman/swift,aschwaighofer/swift,roambotics/swift,aschwaighofer/swift,parkera/swift,stephentyrone/swift,devincoughlin/swift,parkera/swift,shahmishal/swift,roambotics/swift,hooman/swift,nathawes/swift,roambotics/swift,devincoughlin/swift,gregomni/swift,lorentey/swift,shahmishal/swift,lorentey/swift,airspeedswift/swift,benlangmuir/swift,shahmishal/swift,lorentey/swift,jmgc/swift,jckarter/swift,stephentyrone/swift,hooman/swift,rudkx/swift,devincoughlin/swift,devincoughlin/swift,jckarter/swift,apple/swift,airspeedswift/swift,gribozavr/swift,karwa/swift,parkera/swift,allevato/swift,aschwaighofer/swift,karwa/swift,karwa/swift,airspeedswift/swift,xwu/swift,JGiola/swift,sschiau/swift,ahoppen/swift,benlangmuir/swift,nathawes/swift,jmgc/swift,harlanhaskins/swift,lorentey/swift,stephentyrone/swift,karwa/swift,gregomni/swift,sschiau/swift,ahoppen/swift,benlangmuir/swift,JGiola/swift,benlangmuir/swift,parkera/swift,tkremenek/swift,jckarter/swift,shahmishal/swift,CodaFi/swift,roambotics/swift,jckarter/swift,karwa/swift,apple/swift,allevato/swift,sschiau/swift,gribozavr/swift