IRGen: address TODO for COMDATing
IRGen: address TODO for COMDATing

Enable COMDATing in `createFunction`.  This is particularly important
for the emission of the GetEnumTagSinglePayload.  The function emission
is marked as linkonce ODR but does not get COMDAT'ed currently, breaking
emission on PE/COFF targets like Windows.

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