[loop-arc] Do not run LoopARCAnalysis on functions with external declarations.
[loop-arc] Do not run LoopARCAnalysis on functions with external declarations.

I have been able to run LoopRegionAnalysis in the normal pileline and compile
the stdlib so I think this may not be /needed/, but why not save some compile
time and potentially avoid future correctness errors.

Swift SVN r32755

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