[PrintAsObjC] Use TypeDeclFinder instead of custom TypeVisitor (#27189)
[PrintAsObjC] Use TypeDeclFinder instead of custom TypeVisitor (#27189)

This is the same type-walking logic we use for access control
checking, so it had better be correct. Perfect case for DRY!

No functionality change.
rudkx/swift,benlangmuir/swift,CodaFi/swift,gregomni/swift,atrick/swift,jmgc/swift,stephentyrone/swift,tkremenek/swift,karwa/swift,devincoughlin/swift,nathawes/swift,lorentey/swift,roambotics/swift,airspeedswift/swift,xwu/swift,gregomni/swift,gribozavr/swift,devincoughlin/swift,hooman/swift,roambotics/swift,jmgc/swift,karwa/swift,allevato/swift,allevato/swift,nathawes/swift,hooman/swift,sschiau/swift,karwa/swift,CodaFi/swift,allevato/swift,parkera/swift,hooman/swift,apple/swift,apple/swift,JGiola/swift,lorentey/swift,xwu/swift,harlanhaskins/swift,JGiola/swift,tkremenek/swift,jckarter/swift,jmgc/swift,tkremenek/swift,jckarter/swift,aschwaighofer/swift,airspeedswift/swift,CodaFi/swift,roambotics/swift,hooman/swift,harlanhaskins/swift,stephentyrone/swift,hooman/swift,benlangmuir/swift,roambotics/swift,jmgc/swift,allevato/swift,sschiau/swift,parkera/swift,aschwaighofer/swift,gribozavr/swift,JGiola/swift,jmgc/swift,harlanhaskins/swift,apple/swift,harlanhaskins/swift,sschiau/swift,airspeedswift/swift,karwa/swift,lorentey/swift,airspeedswift/swift,jckarter/swift,roambotics/swift,CodaFi/swift,tkremenek/swift,rudkx/swift,sschiau/swift,rudkx/swift,glessard/swift,karwa/swift,tkremenek/swift,gribozavr/swift,devincoughlin/swift,lorentey/swift,ahoppen/swift,hooman/swift,CodaFi/swift,apple/swift,stephentyrone/swift,parkera/swift,karwa/swift,sschiau/swift,gribozavr/swift,parkera/swift,benlangmuir/swift,tkremenek/swift,apple/swift,harlanhaskins/swift,rudkx/swift,xwu/swift,lorentey/swift,devincoughlin/swift,allevato/swift,parkera/swift,glessard/swift,lorentey/swift,atrick/swift,roambotics/swift,aschwaighofer/swift,aschwaighofer/swift,CodaFi/swift,parkera/swift,devincoughlin/swift,ahoppen/swift,jmgc/swift,benlangmuir/swift,gribozavr/swift,nathawes/swift,xwu/swift,devincoughlin/swift,xwu/swift,atrick/swift,airspeedswift/swift,parkera/swift,harlanhaskins/swift,airspeedswift/swift,jckarter/swift,aschwaighofer/swift,glessard/swift,ahoppen/swift,stephentyrone/swift,gregomni/swift,nathawes/swift,glessard/swift,rudkx/swift,ahoppen/swift,parkera/swift,xwu/swift,jmgc/swift,glessard/swift,karwa/swift,gribozavr/swift,JGiola/swift,stephentyrone/swift,JGiola/swift,JGiola/swift,nathawes/swift,apple/swift,gregomni/swift,airspeedswift/swift,karwa/swift,allevato/swift,sschiau/swift,sschiau/swift,gribozavr/swift,devincoughlin/swift,sschiau/swift,lorentey/swift,rudkx/swift,gregomni/swift,ahoppen/swift,ahoppen/swift,lorentey/swift,tkremenek/swift,allevato/swift,stephentyrone/swift,nathawes/swift,nathawes/swift,stephentyrone/swift,jckarter/swift,glessard/swift,jckarter/swift,gribozavr/swift,benlangmuir/swift,devincoughlin/swift,hooman/swift,jckarter/swift,benlangmuir/swift,atrick/swift,aschwaighofer/swift,gregomni/swift,aschwaighofer/swift,xwu/swift,CodaFi/swift,harlanhaskins/swift,atrick/swift,atrick/swift