[cmake] Enable cross-module-optimization when compiling swift libraries in release/relwithdebinfo.
[cmake] Enable cross-module-optimization when compiling swift libraries in release/relwithdebinfo.

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