test: adjust the test use to `ls` instead of `find`
test: adjust the test use to `ls` instead of `find`

Rely on the `ls` behaviour of returning a non-zero if there is no
matching pattern.  This should help make the test pass on Windows
and the other targets.

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