[GSB] Use anchors for the keys in the mapping to rewrite tree roots.
[GSB] Use anchors for the keys in the mapping to rewrite tree roots.

Rather than keying the rewrite tree roots on equivalence classes,
which imply a mapping through potential archetypes, key on (canonical)
types that are currently the anchors of equivalence classes.

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