cmake: build swift-swiftsyntax-test only when SwiftSyntax is built. (#18558)
cmake: build swift-swiftsyntax-test only when SwiftSyntax is built. (#18558)

Resolves: rdar://43024275
shajrawi/swift,austinzheng/swift,nathawes/swift,practicalswift/swift,danielmartin/swift,ahoppen/swift,CodaFi/swift,JGiola/swift,parkera/swift,karwa/swift,glessard/swift,shahmishal/swift,nathawes/swift,apple/swift,lorentey/swift,brentdax/swift,lorentey/swift,danielmartin/swift,natecook1000/swift,JGiola/swift,lorentey/swift,xwu/swift,allevato/swift,karwa/swift,hooman/swift,sschiau/swift,lorentey/swift,benlangmuir/swift,glessard/swift,jmgc/swift,lorentey/swift,natecook1000/swift,JGiola/swift,parkera/swift,gregomni/swift,gregomni/swift,practicalswift/swift,sschiau/swift,austinzheng/swift,gregomni/swift,jmgc/swift,CodaFi/swift,apple/swift,karwa/swift,amraboelela/swift,natecook1000/swift,alblue/swift,tkremenek/swift,apple/swift,natecook1000/swift,austinzheng/swift,jckarter/swift,airspeedswift/swift,shajrawi/swift,alblue/swift,xwu/swift,jmgc/swift,alblue/swift,roambotics/swift,practicalswift/swift,glessard/swift,danielmartin/swift,harlanhaskins/swift,xwu/swift,danielmartin/swift,xwu/swift,devincoughlin/swift,shahmishal/swift,stephentyrone/swift,airspeedswift/swift,brentdax/swift,nathawes/swift,CodaFi/swift,sschiau/swift,jmgc/swift,hooman/swift,jmgc/swift,amraboelela/swift,shajrawi/swift,allevato/swift,roambotics/swift,harlanhaskins/swift,practicalswift/swift,CodaFi/swift,brentdax/swift,gribozavr/swift,devincoughlin/swift,benlangmuir/swift,gribozavr/swift,shajrawi/swift,parkera/swift,jckarter/swift,jmgc/swift,austinzheng/swift,JGiola/swift,shahmishal/swift,ahoppen/swift,rudkx/swift,parkera/swift,brentdax/swift,shahmishal/swift,airspeedswift/swift,sschiau/swift,natecook1000/swift,tkremenek/swift,glessard/swift,hooman/swift,devincoughlin/swift,amraboelela/swift,apple/swift,karwa/swift,rudkx/swift,gregomni/swift,airspeedswift/swift,natecook1000/swift,austinzheng/swift,alblue/swift,austinzheng/swift,lorentey/swift,jmgc/swift,apple/swift,danielmartin/swift,devincoughlin/swift,stephentyrone/swift,stephentyrone/swift,danielmartin/swift,brentdax/swift,gregomni/swift,alblue/swift,CodaFi/swift,tkremenek/swift,practicalswift/swift,alblue/swift,xedin/swift,parkera/swift,shahmishal/swift,roambotics/swift,amraboelela/swift,atrick/swift,jckarter/swift,parkera/swift,natecook1000/swift,xedin/swift,ahoppen/swift,amraboelela/swift,shajrawi/swift,sschiau/swift,xedin/swift,sschiau/swift,benlangmuir/swift,roambotics/swift,harlanhaskins/swift,nathawes/swift,practicalswift/swift,rudkx/swift,harlanhaskins/swift,gribozavr/swift,aschwaighofer/swift,practicalswift/swift,airspeedswift/swift,tkremenek/swift,ahoppen/swift,devincoughlin/swift,gribozavr/swift,practicalswift/swift,airspeedswift/swift,ahoppen/swift,benlangmuir/swift,benlangmuir/swift,atrick/swift,xedin/swift,allevato/swift,allevato/swift,shajrawi/swift,sschiau/swift,brentdax/swift,amraboelela/swift,aschwaighofer/swift,brentdax/swift,gregomni/swift,gribozavr/swift,xwu/swift,gribozavr/swift,xedin/swift,shahmishal/swift,jckarter/swift,hooman/swift,xwu/swift,roambotics/swift,xwu/swift,nathawes/swift,shahmishal/swift,shahmishal/swift,karwa/swift,harlanhaskins/swift,xedin/swift,karwa/swift,JGiola/swift,austinzheng/swift,hooman/swift,ahoppen/swift,parkera/swift,hooman/swift,lorentey/swift,stephentyrone/swift,parkera/swift,jckarter/swift,xedin/swift,devincoughlin/swift,alblue/swift,aschwaighofer/swift,CodaFi/swift,stephentyrone/swift,jckarter/swift,atrick/swift,atrick/swift,karwa/swift,harlanhaskins/swift,gribozavr/swift,CodaFi/swift,harlanhaskins/swift,aschwaighofer/swift,gribozavr/swift,rudkx/swift,shajrawi/swift,roambotics/swift,aschwaighofer/swift,sschiau/swift,hooman/swift,devincoughlin/swift,allevato/swift,JGiola/swift,apple/swift,rudkx/swift,aschwaighofer/swift,karwa/swift,glessard/swift,glessard/swift,devincoughlin/swift,jckarter/swift,tkremenek/swift,benlangmuir/swift,danielmartin/swift,airspeedswift/swift,nathawes/swift,tkremenek/swift,xedin/swift,allevato/swift,amraboelela/swift,stephentyrone/swift,allevato/swift,tkremenek/swift,aschwaighofer/swift,rudkx/swift,stephentyrone/swift,shajrawi/swift,lorentey/swift,atrick/swift,nathawes/swift,atrick/swift