Revert "Add -Wextra-semi to list of warnings to build Swift with."
Revert "Add -Wextra-semi to list of warnings to build Swift with."

This is turning up warnings in LLVM's headers.

Swift SVN r15492

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