Small clean-ups to Type::join.
Small clean-ups to Type::join.

We shouldn't need to check for Type() in getSuperclassJoin(). We can
also just call join() directly rather than TypeJoin::join(), since it's
the only join() in scope.

jopamer/swift,aschwaighofer/swift,shajrawi/swift,huonw/swift,jmgc/swift,tjw/swift,shajrawi/swift,amraboelela/swift,shahmishal/swift,parkera/swift,airspeedswift/swift,atrick/swift,frootloops/swift,stephentyrone/swift,austinzheng/swift,lorentey/swift,frootloops/swift,ahoppen/swift,alblue/swift,CodaFi/swift,gribozavr/swift,atrick/swift,xedin/swift,sschiau/swift,gribozavr/swift,gribozavr/swift,karwa/swift,tkremenek/swift,jckarter/swift,ahoppen/swift,tkremenek/swift,stephentyrone/swift,sschiau/swift,karwa/swift,benlangmuir/swift,lorentey/swift,huonw/swift,apple/swift,natecook1000/swift,brentdax/swift,jckarter/swift,shahmishal/swift,nathawes/swift,tjw/swift,practicalswift/swift,swiftix/swift,harlanhaskins/swift,airspeedswift/swift,parkera/swift,shajrawi/swift,shahmishal/swift,jckarter/swift,austinzheng/swift,nathawes/swift,airspeedswift/swift,rudkx/swift,alblue/swift,shahmishal/swift,glessard/swift,natecook1000/swift,karwa/swift,glessard/swift,tjw/swift,jopamer/swift,gribozavr/swift,parkera/swift,hooman/swift,gregomni/swift,aschwaighofer/swift,rudkx/swift,apple/swift,airspeedswift/swift,practicalswift/swift,roambotics/swift,swiftix/swift,jopamer/swift,practicalswift/swift,CodaFi/swift,shahmishal/swift,sschiau/swift,tjw/swift,amraboelela/swift,tkremenek/swift,harlanhaskins/swift,shajrawi/swift,allevato/swift,natecook1000/swift,aschwaighofer/swift,OscarSwanros/swift,jmgc/swift,ahoppen/swift,lorentey/swift,rudkx/swift,natecook1000/swift,gribozavr/swift,JGiola/swift,aschwaighofer/swift,CodaFi/swift,ahoppen/swift,huonw/swift,stephentyrone/swift,zisko/swift,CodaFi/swift,hooman/swift,xwu/swift,practicalswift/swift,nathawes/swift,karwa/swift,apple/swift,shajrawi/swift,xedin/swift,sschiau/swift,tkremenek/swift,hooman/swift,lorentey/swift,jckarter/swift,benlangmuir/swift,xwu/swift,alblue/swift,brentdax/swift,tkremenek/swift,parkera/swift,zisko/swift,harlanhaskins/swift,lorentey/swift,sschiau/swift,glessard/swift,brentdax/swift,shajrawi/swift,danielmartin/swift,glessard/swift,lorentey/swift,xedin/swift,zisko/swift,rudkx/swift,devincoughlin/swift,huonw/swift,karwa/swift,huonw/swift,lorentey/swift,allevato/swift,atrick/swift,practicalswift/swift,jopamer/swift,atrick/swift,practicalswift/swift,shahmishal/swift,allevato/swift,rudkx/swift,zisko/swift,tkremenek/swift,shajrawi/swift,austinzheng/swift,gregomni/swift,amraboelela/swift,practicalswift/swift,apple/swift,practicalswift/swift,alblue/swift,frootloops/swift,swiftix/swift,JGiola/swift,devincoughlin/swift,jckarter/swift,nathawes/swift,benlangmuir/swift,gribozavr/swift,brentdax/swift,alblue/swift,benlangmuir/swift,devincoughlin/swift,roambotics/swift,natecook1000/swift,JGiola/swift,OscarSwanros/swift,gregomni/swift,parkera/swift,allevato/swift,CodaFi/swift,amraboelela/swift,austinzheng/swift,danielmartin/swift,hooman/swift,benlangmuir/swift,tjw/swift,aschwaighofer/swift,OscarSwanros/swift,roambotics/swift,glessard/swift,frootloops/swift,jckarter/swift,xedin/swift,ahoppen/swift,stephentyrone/swift,CodaFi/swift,jmgc/swift,jopamer/swift,huonw/swift,roambotics/swift,amraboelela/swift,tkremenek/swift,xwu/swift,jopamer/swift,brentdax/swift,danielmartin/swift,natecook1000/swift,brentdax/swift,nathawes/swift,apple/swift,natecook1000/swift,swiftix/swift,roambotics/swift,roambotics/swift,glessard/swift,shahmishal/swift,JGiola/swift,stephentyrone/swift,shahmishal/swift,zisko/swift,harlanhaskins/swift,allevato/swift,danielmartin/swift,xedin/swift,allevato/swift,sschiau/swift,gregomni/swift,aschwaighofer/swift,devincoughlin/swift,danielmartin/swift,harlanhaskins/swift,gregomni/swift,parkera/swift,shajrawi/swift,xedin/swift,alblue/swift,danielmartin/swift,rudkx/swift,jmgc/swift,zisko/swift,hooman/swift,harlanhaskins/swift,amraboelela/swift,swiftix/swift,jmgc/swift,karwa/swift,atrick/swift,JGiola/swift,benlangmuir/swift,aschwaighofer/swift,harlanhaskins/swift,JGiola/swift,frootloops/swift,danielmartin/swift,parkera/swift,hooman/swift,devincoughlin/swift,apple/swift,tjw/swift,nathawes/swift,gribozavr/swift,jmgc/swift,karwa/swift,huonw/swift,devincoughlin/swift,austinzheng/swift,airspeedswift/swift,stephentyrone/swift,devincoughlin/swift,CodaFi/swift,sschiau/swift,jmgc/swift,ahoppen/swift,allevato/swift,hooman/swift,brentdax/swift,alblue/swift,xwu/swift,nathawes/swift,xedin/swift,frootloops/swift,xedin/swift,xwu/swift,parkera/swift,OscarSwanros/swift,atrick/swift,zisko/swift,austinzheng/swift,karwa/swift,OscarSwanros/swift,gribozavr/swift,xwu/swift,lorentey/swift,airspeedswift/swift,xwu/swift,jopamer/swift,swiftix/swift,gregomni/swift,stephentyrone/swift,jckarter/swift,OscarSwanros/swift,austinzheng/swift,devincoughlin/swift,sschiau/swift,amraboelela/swift,tjw/swift,frootloops/swift,swiftix/swift,OscarSwanros/swift,airspeedswift/swift