Remove use of CallGraph in Function Signature Optimization.
Remove use of CallGraph in Function Signature Optimization.

The CallGraph Analysis (as we know it today) is going away. This commit replaces
the use of the call graph with a local implementation of a basic scan of the
module that constructs the caller-callee listing. The only functionality that we
keep is the bottom-up function order, and this is not going away.

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