[Runtime] Remove ObjCMirrors.swift, which is no longer used after the Mirror reimplementation in #14678.
[Runtime] Remove ObjCMirrors.swift, which is no longer used after the Mirror reimplementation in #14678.

rdar://problem/20356017
stephentyrone/swift,shajrawi/swift,parkera/swift,jckarter/swift,apple/swift,roambotics/swift,gribozavr/swift,tkremenek/swift,roambotics/swift,xwu/swift,lorentey/swift,brentdax/swift,atrick/swift,gribozavr/swift,stephentyrone/swift,gregomni/swift,gregomni/swift,xedin/swift,shajrawi/swift,xedin/swift,apple/swift,xedin/swift,harlanhaskins/swift,roambotics/swift,brentdax/swift,xedin/swift,ahoppen/swift,tjw/swift,lorentey/swift,allevato/swift,brentdax/swift,austinzheng/swift,allevato/swift,natecook1000/swift,austinzheng/swift,glessard/swift,harlanhaskins/swift,JGiola/swift,gribozavr/swift,shahmishal/swift,sschiau/swift,gribozavr/swift,sschiau/swift,karwa/swift,danielmartin/swift,karwa/swift,lorentey/swift,amraboelela/swift,parkera/swift,airspeedswift/swift,jmgc/swift,tkremenek/swift,hooman/swift,huonw/swift,sschiau/swift,sschiau/swift,jckarter/swift,brentdax/swift,allevato/swift,parkera/swift,devincoughlin/swift,jopamer/swift,stephentyrone/swift,apple/swift,jopamer/swift,xwu/swift,parkera/swift,shahmishal/swift,austinzheng/swift,natecook1000/swift,aschwaighofer/swift,shajrawi/swift,danielmartin/swift,tjw/swift,karwa/swift,nathawes/swift,benlangmuir/swift,devincoughlin/swift,rudkx/swift,glessard/swift,shajrawi/swift,parkera/swift,gregomni/swift,CodaFi/swift,roambotics/swift,xedin/swift,danielmartin/swift,benlangmuir/swift,airspeedswift/swift,alblue/swift,harlanhaskins/swift,ahoppen/swift,shajrawi/swift,austinzheng/swift,JGiola/swift,nathawes/swift,allevato/swift,alblue/swift,devincoughlin/swift,JGiola/swift,jopamer/swift,benlangmuir/swift,lorentey/swift,rudkx/swift,shajrawi/swift,tjw/swift,jopamer/swift,devincoughlin/swift,jckarter/swift,natecook1000/swift,amraboelela/swift,austinzheng/swift,airspeedswift/swift,alblue/swift,stephentyrone/swift,roambotics/swift,hooman/swift,danielmartin/swift,aschwaighofer/swift,harlanhaskins/swift,gribozavr/swift,practicalswift/swift,sschiau/swift,hooman/swift,hooman/swift,huonw/swift,practicalswift/swift,nathawes/swift,jmgc/swift,tkremenek/swift,nathawes/swift,stephentyrone/swift,stephentyrone/swift,practicalswift/swift,shajrawi/swift,lorentey/swift,alblue/swift,xedin/swift,practicalswift/swift,practicalswift/swift,shahmishal/swift,harlanhaskins/swift,xedin/swift,lorentey/swift,allevato/swift,glessard/swift,alblue/swift,brentdax/swift,xwu/swift,jmgc/swift,lorentey/swift,ahoppen/swift,devincoughlin/swift,aschwaighofer/swift,parkera/swift,amraboelela/swift,hooman/swift,harlanhaskins/swift,gribozavr/swift,xwu/swift,jmgc/swift,apple/swift,aschwaighofer/swift,glessard/swift,nathawes/swift,stephentyrone/swift,shahmishal/swift,glessard/swift,sschiau/swift,xwu/swift,aschwaighofer/swift,aschwaighofer/swift,gregomni/swift,rudkx/swift,jckarter/swift,amraboelela/swift,tkremenek/swift,huonw/swift,shahmishal/swift,CodaFi/swift,danielmartin/swift,tjw/swift,amraboelela/swift,JGiola/swift,devincoughlin/swift,practicalswift/swift,lorentey/swift,nathawes/swift,tjw/swift,natecook1000/swift,devincoughlin/swift,rudkx/swift,gribozavr/swift,jckarter/swift,gregomni/swift,jopamer/swift,JGiola/swift,atrick/swift,roambotics/swift,atrick/swift,ahoppen/swift,harlanhaskins/swift,tkremenek/swift,karwa/swift,atrick/swift,austinzheng/swift,allevato/swift,jmgc/swift,ahoppen/swift,brentdax/swift,jopamer/swift,practicalswift/swift,benlangmuir/swift,jmgc/swift,tkremenek/swift,CodaFi/swift,huonw/swift,benlangmuir/swift,xwu/swift,CodaFi/swift,natecook1000/swift,hooman/swift,jmgc/swift,apple/swift,sschiau/swift,alblue/swift,gribozavr/swift,danielmartin/swift,natecook1000/swift,practicalswift/swift,danielmartin/swift,rudkx/swift,JGiola/swift,shahmishal/swift,tjw/swift,shahmishal/swift,jopamer/swift,airspeedswift/swift,tjw/swift,sschiau/swift,brentdax/swift,ahoppen/swift,nathawes/swift,xedin/swift,CodaFi/swift,allevato/swift,shahmishal/swift,airspeedswift/swift,devincoughlin/swift,parkera/swift,atrick/swift,huonw/swift,apple/swift,karwa/swift,karwa/swift,aschwaighofer/swift,CodaFi/swift,jckarter/swift,amraboelela/swift,natecook1000/swift,rudkx/swift,airspeedswift/swift,shajrawi/swift,CodaFi/swift,amraboelela/swift,huonw/swift,karwa/swift,gregomni/swift,parkera/swift,karwa/swift,huonw/swift,glessard/swift,tkremenek/swift,airspeedswift/swift,hooman/swift,benlangmuir/swift,alblue/swift,xwu/swift,austinzheng/swift,atrick/swift,jckarter/swift