[CMake] Generate swiftinterface files next to the stdlib swiftmodules
[CMake] Generate swiftinterface files next to the stdlib swiftmodules

We're not using them for anything yet, but this will exercise
-emit-interface while we're working on it and make sure that it
doesn't crash when processing complex code like the standard library.

aschwaighofer/swift,jckarter/swift,gribozavr/swift,tkremenek/swift,allevato/swift,nathawes/swift,airspeedswift/swift,sschiau/swift,lorentey/swift,jckarter/swift,atrick/swift,alblue/swift,danielmartin/swift,roambotics/swift,shajrawi/swift,harlanhaskins/swift,gregomni/swift,karwa/swift,lorentey/swift,jckarter/swift,alblue/swift,shahmishal/swift,JGiola/swift,gregomni/swift,allevato/swift,JGiola/swift,practicalswift/swift,shahmishal/swift,hooman/swift,atrick/swift,xwu/swift,tkremenek/swift,practicalswift/swift,allevato/swift,atrick/swift,devincoughlin/swift,rudkx/swift,stephentyrone/swift,xwu/swift,gribozavr/swift,glessard/swift,parkera/swift,rudkx/swift,alblue/swift,shajrawi/swift,practicalswift/swift,stephentyrone/swift,shahmishal/swift,harlanhaskins/swift,harlanhaskins/swift,lorentey/swift,danielmartin/swift,austinzheng/swift,brentdax/swift,tkremenek/swift,nathawes/swift,benlangmuir/swift,amraboelela/swift,stephentyrone/swift,natecook1000/swift,jmgc/swift,sschiau/swift,lorentey/swift,harlanhaskins/swift,glessard/swift,karwa/swift,rudkx/swift,xedin/swift,gribozavr/swift,CodaFi/swift,karwa/swift,allevato/swift,airspeedswift/swift,xwu/swift,glessard/swift,glessard/swift,lorentey/swift,alblue/swift,jckarter/swift,karwa/swift,parkera/swift,gribozavr/swift,hooman/swift,jmgc/swift,jckarter/swift,amraboelela/swift,xedin/swift,xwu/swift,parkera/swift,roambotics/swift,devincoughlin/swift,hooman/swift,aschwaighofer/swift,roambotics/swift,glessard/swift,nathawes/swift,aschwaighofer/swift,aschwaighofer/swift,shajrawi/swift,sschiau/swift,shahmishal/swift,alblue/swift,harlanhaskins/swift,gribozavr/swift,stephentyrone/swift,devincoughlin/swift,brentdax/swift,CodaFi/swift,danielmartin/swift,xwu/swift,brentdax/swift,apple/swift,JGiola/swift,xedin/swift,xwu/swift,atrick/swift,natecook1000/swift,JGiola/swift,devincoughlin/swift,tkremenek/swift,jckarter/swift,amraboelela/swift,gregomni/swift,shahmishal/swift,allevato/swift,nathawes/swift,glessard/swift,gregomni/swift,xwu/swift,stephentyrone/swift,airspeedswift/swift,gribozavr/swift,nathawes/swift,amraboelela/swift,austinzheng/swift,shajrawi/swift,jckarter/swift,tkremenek/swift,practicalswift/swift,allevato/swift,practicalswift/swift,austinzheng/swift,amraboelela/swift,aschwaighofer/swift,airspeedswift/swift,rudkx/swift,apple/swift,xedin/swift,shajrawi/swift,rudkx/swift,practicalswift/swift,harlanhaskins/swift,gribozavr/swift,shahmishal/swift,jmgc/swift,JGiola/swift,danielmartin/swift,shahmishal/swift,natecook1000/swift,benlangmuir/swift,atrick/swift,karwa/swift,airspeedswift/swift,devincoughlin/swift,natecook1000/swift,benlangmuir/swift,danielmartin/swift,CodaFi/swift,ahoppen/swift,ahoppen/swift,karwa/swift,karwa/swift,karwa/swift,apple/swift,practicalswift/swift,nathawes/swift,sschiau/swift,brentdax/swift,stephentyrone/swift,allevato/swift,stephentyrone/swift,sschiau/swift,lorentey/swift,devincoughlin/swift,jmgc/swift,xedin/swift,CodaFi/swift,practicalswift/swift,shajrawi/swift,hooman/swift,atrick/swift,CodaFi/swift,benlangmuir/swift,sschiau/swift,jmgc/swift,alblue/swift,brentdax/swift,hooman/swift,apple/swift,devincoughlin/swift,alblue/swift,ahoppen/swift,austinzheng/swift,jmgc/swift,benlangmuir/swift,natecook1000/swift,parkera/swift,gregomni/swift,roambotics/swift,jmgc/swift,xedin/swift,austinzheng/swift,tkremenek/swift,ahoppen/swift,danielmartin/swift,xedin/swift,parkera/swift,lorentey/swift,natecook1000/swift,brentdax/swift,ahoppen/swift,nathawes/swift,xedin/swift,danielmartin/swift,lorentey/swift,brentdax/swift,austinzheng/swift,ahoppen/swift,hooman/swift,amraboelela/swift,shahmishal/swift,aschwaighofer/swift,gribozavr/swift,aschwaighofer/swift,roambotics/swift,parkera/swift,roambotics/swift,austinzheng/swift,airspeedswift/swift,parkera/swift,benlangmuir/swift,rudkx/swift,apple/swift,apple/swift,airspeedswift/swift,parkera/swift,JGiola/swift,devincoughlin/swift,amraboelela/swift,CodaFi/swift,CodaFi/swift,natecook1000/swift,shajrawi/swift,sschiau/swift,harlanhaskins/swift,hooman/swift,shajrawi/swift,sschiau/swift,gregomni/swift,tkremenek/swift