Add cplusplus_driver lit feature
Add cplusplus_driver lit feature

This will be used to mark tests as REQUIRES: cplusplus_driver if
they cannot be easily made to work with swift-driver due to architectural differences
(for example, the lack of -driver-print-actions), and the test cases have been ported to XCTest

This feature is enabled if the swift_driver param is NOT passed to lit.py

apple/swift,parkera/swift,tkremenek/swift,tkremenek/swift,rudkx/swift,ahoppen/swift,roambotics/swift,jmgc/swift,gregomni/swift,JGiola/swift,nathawes/swift,jmgc/swift,rudkx/swift,glessard/swift,tkremenek/swift,roambotics/swift,xwu/swift,atrick/swift,jmgc/swift,apple/swift,parkera/swift,nathawes/swift,JGiola/swift,gregomni/swift,atrick/swift,parkera/swift,parkera/swift,benlangmuir/swift,JGiola/swift,glessard/swift,apple/swift,glessard/swift,rudkx/swift,hooman/swift,hooman/swift,tkremenek/swift,JGiola/swift,parkera/swift,xwu/swift,jmgc/swift,ahoppen/swift,ahoppen/swift,ahoppen/swift,gregomni/swift,rudkx/swift,hooman/swift,nathawes/swift,atrick/swift,jmgc/swift,gregomni/swift,hooman/swift,apple/swift,tkremenek/swift,atrick/swift,JGiola/swift,tkremenek/swift,roambotics/swift,jmgc/swift,hooman/swift,gregomni/swift,glessard/swift,roambotics/swift,nathawes/swift,benlangmuir/swift,xwu/swift,atrick/swift,nathawes/swift,parkera/swift,rudkx/swift,apple/swift,tkremenek/swift,xwu/swift,roambotics/swift,rudkx/swift,ahoppen/swift,JGiola/swift,gregomni/swift,benlangmuir/swift,hooman/swift,roambotics/swift,jmgc/swift,benlangmuir/swift,hooman/swift,benlangmuir/swift,parkera/swift,nathawes/swift,glessard/swift,xwu/swift,xwu/swift,ahoppen/swift,glessard/swift,parkera/swift,apple/swift,xwu/swift,nathawes/swift,benlangmuir/swift,atrick/swift