TypeChecker: Remove the notion of "external decls we've already handled".
TypeChecker: Remove the notion of "external decls we've already handled".

There's no reason to check these before everything else. We'll still check
them in the main processing loop of performTypeChecking.

(There are cases where we create a type checker outside of
performTypeChecking, but the existing code doesn't handle that properly
either -- it doesn't call handleExternalDecl for new decls being brought
in. If this turns out to be an issue, we can restore the loop and fix that
issue.)

Swift SVN r15353

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