IRGen: Simplify LinkInfo::createVariable()
IRGen: Simplify LinkInfo::createVariable()

llvm::Module::getNamedGlobal() already returns an llvm::GlobalVariable;
no need to cast. NFC

Swift SVN r27808

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