Fix build-script --dump-config
Fix build-script --dump-config

The Version object used __slots__ instead of __dict__, so it was not serializable. Update JSONDumper to stringify objects if vars() won’t work.

This change does not update any tests because build-script does not currently have a way to write full-script integration tests.

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