Revert "[FunctionSigOpt] Callee set construction does not need to be bottom-up."
Revert "[FunctionSigOpt] Callee set construction does not need to be bottom-up."

This reverts commit 38190816dae28f60772a4dea40518c01f5b5a36e.

Implicated in build breakage.

Jnosh/swift,CodaFi/swift,rudkx/swift,tardieu/swift,therealbnut/swift,JaSpa/swift,tardieu/swift,gottesmm/swift,swiftix/swift,arvedviehweger/swift,gribozavr/swift,russbishop/swift,atrick/swift,johnno1962d/swift,stephentyrone/swift,kentya6/swift,brentdax/swift,parkera/swift,sdulal/swift,brentdax/swift,gottesmm/swift,modocache/swift,ken0nek/swift,sschiau/swift,practicalswift/swift,karwa/swift,parkera/swift,russbishop/swift,deyton/swift,deyton/swift,KrishMunot/swift,KrishMunot/swift,alblue/swift,allevato/swift,sschiau/swift,ken0nek/swift,harlanhaskins/swift,milseman/swift,jckarter/swift,bitjammer/swift,aschwaighofer/swift,swiftix/swift.old,allevato/swift,zisko/swift,practicalswift/swift,MukeshKumarS/Swift,shahmishal/swift,devincoughlin/swift,tkremenek/swift,slavapestov/swift,hooman/swift,gmilos/swift,adrfer/swift,swiftix/swift.old,russbishop/swift,practicalswift/swift,russbishop/swift,Ivacker/swift,harlanhaskins/swift,brentdax/swift,manavgabhawala/swift,return/swift,frootloops/swift,hooman/swift,OscarSwanros/swift,calebd/swift,codestergit/swift,jtbandes/swift,xwu/swift,bitjammer/swift,huonw/swift,kentya6/swift,milseman/swift,hughbe/swift,brentdax/swift,slavapestov/swift,calebd/swift,OscarSwanros/swift,glessard/swift,uasys/swift,shajrawi/swift,johnno1962d/swift,tjw/swift,alblue/swift,atrick/swift,glessard/swift,nathawes/swift,milseman/swift,benlangmuir/swift,hughbe/swift,jckarter/swift,CodaFi/swift,atrick/swift,JGiola/swift,atrick/swift,gregomni/swift,roambotics/swift,JaSpa/swift,modocache/swift,xwu/swift,JaSpa/swift,swiftix/swift,amraboelela/swift,devincoughlin/swift,cbrentharris/swift,arvedviehweger/swift,kstaring/swift,MukeshKumarS/Swift,CodaFi/swift,kperryua/swift,lorentey/swift,stephentyrone/swift,parkera/swift,airspeedswift/swift,alblue/swift,ben-ng/swift,shahmishal/swift,ahoppen/swift,gribozavr/swift,sdulal/swift,benlangmuir/swift,karwa/swift,danielmartin/swift,tardieu/swift,dduan/swift,amraboelela/swift,jmgc/swift,return/swift,apple/swift,dduan/swift,gregomni/swift,hooman/swift,OscarSwanros/swift,austinzheng/swift,IngmarStein/swift,IngmarStein/swift,SwiftAndroid/swift,kusl/swift,shahmishal/swift,tkremenek/swift,swiftix/swift.old,stephentyrone/swift,gribozavr/swift,ben-ng/swift,kperryua/swift,khizkhiz/swift,natecook1000/swift,gottesmm/swift,tjw/swift,codestergit/swift,hooman/swift,alblue/swift,apple/swift,huonw/swift,cbrentharris/swift,apple/swift,xedin/swift,gribozavr/swift,emilstahl/swift,shajrawi/swift,KrishMunot/swift,dduan/swift,kperryua/swift,alblue/swift,bitjammer/swift,sdulal/swift,atrick/swift,kusl/swift,manavgabhawala/swift,felix91gr/swift,xedin/swift,xwu/swift,ahoppen/swift,KrishMunot/swift,mightydeveloper/swift,dduan/swift,frootloops/swift,SwiftAndroid/swift,Jnosh/swift,ahoppen/swift,kusl/swift,natecook1000/swift,cbrentharris/swift,therealbnut/swift,gmilos/swift,Ivacker/swift,hooman/swift,JGiola/swift,slavapestov/swift,jopamer/swift,tinysun212/swift-windows,zisko/swift,shajrawi/swift,swiftix/swift,JaSpa/swift,roambotics/swift,return/swift,nathawes/swift,huonw/swift,arvedviehweger/swift,jtbandes/swift,practicalswift/swift,LeoShimonaka/swift,harlanhaskins/swift,danielmartin/swift,swiftix/swift.old,kentya6/swift,ahoppen/swift,devincoughlin/swift,bitjammer/swift,adrfer/swift,roambotics/swift,nathawes/swift,parkera/swift,rudkx/swift,khizkhiz/swift,sschiau/swift,gregomni/swift,devincoughlin/swift,tkremenek/swift,LeoShimonaka/swift,rudkx/swift,LeoShimonaka/swift,gmilos/swift,cbrentharris/swift,stephentyrone/swift,gmilos/swift,gregomni/swift,Jnosh/swift,stephentyrone/swift,apple/swift,airspeedswift/swift,codestergit/swift,adrfer/swift,xedin/swift,jopamer/swift,benlangmuir/swift,harlanhaskins/swift,glessard/swift,SwiftAndroid/swift,aschwaighofer/swift,brentdax/swift,lorentey/swift,bitjammer/swift,uasys/swift,kstaring/swift,swiftix/swift,amraboelela/swift,sdulal/swift,emilstahl/swift,KrishMunot/swift,modocache/swift,tinysun212/swift-windows,cbrentharris/swift,therealbnut/swift,kusl/swift,gribozavr/swift,felix91gr/swift,aschwaighofer/swift,parkera/swift,tinysun212/swift-windows,ben-ng/swift,karwa/swift,allevato/swift,hooman/swift,aschwaighofer/swift,milseman/swift,danielmartin/swift,frootloops/swift,devincoughlin/swift,sdulal/swift,khizkhiz/swift,allevato/swift,huonw/swift,frootloops/swift,codestergit/swift,jopamer/swift,Ivacker/swift,nathawes/swift,swiftix/swift.old,austinzheng/swift,swiftix/swift.old,MukeshKumarS/Swift,shahmishal/swift,lorentey/swift,modocache/swift,LeoShimonaka/swift,CodaFi/swift,deyton/swift,austinzheng/swift,tinysun212/swift-windows,allevato/swift,kusl/swift,airspeedswift/swift,OscarSwanros/swift,JGiola/swift,milseman/swift,harlanhaskins/swift,shajrawi/swift,arvedviehweger/swift,sschiau/swift,johnno1962d/swift,OscarSwanros/swift,gottesmm/swift,lorentey/swift,mightydeveloper/swift,KrishMunot/swift,gribozavr/swift,felix91gr/swift,slavapestov/swift,lorentey/swift,return/swift,mightydeveloper/swift,deyton/swift,roambotics/swift,tinysun212/swift-windows,dreamsxin/swift,emilstahl/swift,sdulal/swift,jtbandes/swift,benlangmuir/swift,IngmarStein/swift,karwa/swift,tkremenek/swift,kentya6/swift,kstaring/swift,kusl/swift,djwbrown/swift,jmgc/swift,therealbnut/swift,nathawes/swift,apple/swift,KrishMunot/swift,hughbe/swift,emilstahl/swift,airspeedswift/swift,arvedviehweger/swift,brentdax/swift,frootloops/swift,swiftix/swift,jopamer/swift,modocache/swift,karwa/swift,practicalswift/swift,jmgc/swift,tjw/swift,glessard/swift,swiftix/swift.old,rudkx/swift,airspeedswift/swift,jopamer/swift,shahmishal/swift,jckarter/swift,russbishop/swift,brentdax/swift,austinzheng/swift,emilstahl/swift,Jnosh/swift,jmgc/swift,tinysun212/swift-windows,stephentyrone/swift,tkremenek/swift,allevato/swift,mightydeveloper/swift,Ivacker/swift,tardieu/swift,JGiola/swift,zisko/swift,amraboelela/swift,modocache/swift,sschiau/swift,Jnosh/swift,Ivacker/swift,rudkx/swift,deyton/swift,CodaFi/swift,dduan/swift,jmgc/swift,parkera/swift,kusl/swift,calebd/swift,shajrawi/swift,emilstahl/swift,dreamsxin/swift,devincoughlin/swift,benlangmuir/swift,LeoShimonaka/swift,djwbrown/swift,russbishop/swift,jmgc/swift,manavgabhawala/swift,SwiftAndroid/swift,alblue/swift,sdulal/swift,djwbrown/swift,gottesmm/swift,dduan/swift,kstaring/swift,roambotics/swift,felix91gr/swift,khizkhiz/swift,milseman/swift,djwbrown/swift,gmilos/swift,MukeshKumarS/Swift,zisko/swift,tjw/swift,zisko/swift,IngmarStein/swift,danielmartin/swift,return/swift,natecook1000/swift,austinzheng/swift,ahoppen/swift,harlanhaskins/swift,ken0nek/swift,natecook1000/swift,djwbrown/swift,codestergit/swift,ken0nek/swift,uasys/swift,frootloops/swift,jtbandes/swift,Jnosh/swift,airspeedswift/swift,arvedviehweger/swift,xwu/swift,gregomni/swift,austinzheng/swift,IngmarStein/swift,JaSpa/swift,manavgabhawala/swift,kentya6/swift,tkremenek/swift,slavapestov/swift,xwu/swift,harlanhaskins/swift,tinysun212/swift-windows,deyton/swift,practicalswift/swift,LeoShimonaka/swift,xwu/swift,mightydeveloper/swift,SwiftAndroid/swift,khizkhiz/swift,jtbandes/swift,ben-ng/swift,milseman/swift,Ivacker/swift,natecook1000/swift,kentya6/swift,slavapestov/swift,frootloops/swift,Ivacker/swift,kperryua/swift,alblue/swift,danielmartin/swift,MukeshKumarS/Swift,apple/swift,karwa/swift,adrfer/swift,mightydeveloper/swift,emilstahl/swift,hughbe/swift,xedin/swift,swiftix/swift.old,jtbandes/swift,bitjammer/swift,airspeedswift/swift,OscarSwanros/swift,therealbnut/swift,ahoppen/swift,cbrentharris/swift,sschiau/swift,roambotics/swift,johnno1962d/swift,tardieu/swift,sschiau/swift,hughbe/swift,hooman/swift,JaSpa/swift,OscarSwanros/swift,kentya6/swift,amraboelela/swift,therealbnut/swift,zisko/swift,khizkhiz/swift,calebd/swift,kperryua/swift,shahmishal/swift,huonw/swift,jopamer/swift,JGiola/swift,zisko/swift,kstaring/swift,parkera/swift,khizkhiz/swift,practicalswift/swift,huonw/swift,jtbandes/swift,Jnosh/swift,glessard/swift,emilstahl/swift,sschiau/swift,ben-ng/swift,bitjammer/swift,cbrentharris/swift,manavgabhawala/swift,nathawes/swift,nathawes/swift,xedin/swift,return/swift,benlangmuir/swift,karwa/swift,practicalswift/swift,SwiftAndroid/swift,codestergit/swift,lorentey/swift,tardieu/swift,amraboelela/swift,johnno1962d/swift,kperryua/swift,gribozavr/swift,austinzheng/swift,deyton/swift,shahmishal/swift,CodaFi/swift,djwbrown/swift,JaSpa/swift,swiftix/swift,kentya6/swift,manavgabhawala/swift,IngmarStein/swift,calebd/swift,devincoughlin/swift,swiftix/swift,cbrentharris/swift,shahmishal/swift,karwa/swift,uasys/swift,xedin/swift,adrfer/swift,devincoughlin/swift,natecook1000/swift,danielmartin/swift,lorentey/swift,adrfer/swift,jopamer/swift,jckarter/swift,ben-ng/swift,xedin/swift,gmilos/swift,calebd/swift,xedin/swift,CodaFi/swift,uasys/swift,JGiola/swift,felix91gr/swift,amraboelela/swift,tjw/swift,jckarter/swift,dduan/swift,MukeshKumarS/Swift,jckarter/swift,aschwaighofer/swift,gmilos/swift,johnno1962d/swift,hughbe/swift,felix91gr/swift,MukeshKumarS/Swift,felix91gr/swift,stephentyrone/swift,tjw/swift,hughbe/swift,kstaring/swift,ken0nek/swift,gregomni/swift,therealbnut/swift,russbishop/swift,danielmartin/swift,gottesmm/swift,ken0nek/swift,calebd/swift,parkera/swift,johnno1962d/swift,SwiftAndroid/swift,rudkx/swift,sdulal/swift,slavapestov/swift,shajrawi/swift,gottesmm/swift,ken0nek/swift,atrick/swift,ben-ng/swift,manavgabhawala/swift,kstaring/swift,mightydeveloper/swift,codestergit/swift,aschwaighofer/swift,arvedviehweger/swift,lorentey/swift,shajrawi/swift,tardieu/swift,jckarter/swift,Ivacker/swift,modocache/swift,uasys/swift,natecook1000/swift,kusl/swift,mightydeveloper/swift,uasys/swift,LeoShimonaka/swift,xwu/swift,gribozavr/swift,kperryua/swift,glessard/swift,jmgc/swift,tjw/swift,djwbrown/swift,shajrawi/swift,return/swift,tkremenek/swift,IngmarStein/swift,aschwaighofer/swift,allevato/swift,huonw/swift,adrfer/swift,LeoShimonaka/swift