[build-script] Add some standalone stdlib asan variants.
[build-script] Add some standalone stdlib asan variants.

This is useful if one wants to quickly compile a stdlib with asan enabled
without recompiling the toolchain.

benlangmuir/swift,benlangmuir/swift,benlangmuir/swift,atrick/swift,roambotics/swift,apple/swift,rudkx/swift,atrick/swift,roambotics/swift,apple/swift,gregomni/swift,atrick/swift,glessard/swift,gregomni/swift,rudkx/swift,ahoppen/swift,rudkx/swift,roambotics/swift,apple/swift,rudkx/swift,glessard/swift,roambotics/swift,gregomni/swift,gregomni/swift,rudkx/swift,JGiola/swift,benlangmuir/swift,roambotics/swift,glessard/swift,JGiola/swift,glessard/swift,ahoppen/swift,gregomni/swift,atrick/swift,JGiola/swift,ahoppen/swift,gregomni/swift,roambotics/swift,apple/swift,benlangmuir/swift,rudkx/swift,glessard/swift,JGiola/swift,ahoppen/swift,benlangmuir/swift,apple/swift,glessard/swift,ahoppen/swift,atrick/swift,JGiola/swift,apple/swift,ahoppen/swift,JGiola/swift,atrick/swift