[utils] buildbot-script.sh: support user-friendly testing with Ninja builds
[utils] buildbot-script.sh: support user-friendly testing with Ninja builds

Also begin supporting Xcode as a generator.  This used to work, months
ago, but now it's failing to find the llvm bin directory.

Swift SVN r10412

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