Cope with ASTScope being disabled in statement checker.
Cope with ASTScope being disabled in statement checker.

Code completion still disables ASTScope lookup, so fall back to using
the old state in such cases. We'll remove all of this code once code
completion (and LLDB?) move off of the old lookup mechanisms.

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