[test][IDE] Test interface generation with grouping and synthesize extensions on
[test][IDE] Test interface generation with grouping and synthesize extensions on

We weren't testing this combination previously.

Resolves rdar://problem/57009035

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