[MetadataReader] Adapt to newer Objective-C class_rw_t
[MetadataReader] Adapt to newer Objective-C class_rw_t

Newer Objective-C runtimes implement a size optimization in class_rw_t
which requires an additional indirection to get to the class_ro_t pointer.

Thanks to Davide for getting to the bottom of this!

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