[Type check diagnostics] Add already-fixed test case from rdar://problem/56710317.
[Type check diagnostics] Add already-fixed test case from rdar://problem/56710317.

Ensures that we don't regress diagnostics for this case in the future.

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