[String] Remove `_core` which is not used in swift-corelibs-foundation anymore
[String] Remove `_core` which is not used in swift-corelibs-foundation anymore

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