[stdlib] Make Set.isSubset(of:) self-contained; remove standalone function for same
[stdlib] Make Set.isSubset(of:) self-contained; remove standalone function for same

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