[build-presets] Don't build the stress tester in Swift PR testing
[build-presets] Don't build the stress tester in Swift PR testing

The continuous PR status bots don't check out the stress tester
repository and started failing. Don't build the stress tester until the
bots check the repository out.

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