[test] Drop the ability to set a custom 'ld'.
[test] Drop the ability to set a custom 'ld'.

It wasn't being honored by the Swift driver anyway. Use a custom PATH instead.

Swift SVN r20420

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