Allocate a list node explicitly; ilist no longer does it.
Allocate a list node explicitly; ilist no longer does it.

llvm r281184 changed ilist<> to stop allocating nodes implicitly.

(cherry picked from commit 5d5be4dc22422f52a3c293e3feccc624fa404146)

hughbe/swift,airspeedswift/swift,glessard/swift,gribozavr/swift,hughbe/swift,shahmishal/swift,stephentyrone/swift,devincoughlin/swift,shahmishal/swift,djwbrown/swift,frootloops/swift,return/swift,natecook1000/swift,swiftix/swift,therealbnut/swift,xedin/swift,gmilos/swift,alblue/swift,JGiola/swift,aschwaighofer/swift,calebd/swift,karwa/swift,parkera/swift,deyton/swift,CodaFi/swift,huonw/swift,frootloops/swift,jckarter/swift,CodaFi/swift,manavgabhawala/swift,amraboelela/swift,aschwaighofer/swift,aschwaighofer/swift,tardieu/swift,uasys/swift,nathawes/swift,harlanhaskins/swift,OscarSwanros/swift,brentdax/swift,tkremenek/swift,bitjammer/swift,shajrawi/swift,parkera/swift,ahoppen/swift,calebd/swift,tkremenek/swift,nathawes/swift,harlanhaskins/swift,JGiola/swift,xedin/swift,hooman/swift,therealbnut/swift,xedin/swift,austinzheng/swift,roambotics/swift,bitjammer/swift,atrick/swift,hughbe/swift,ahoppen/swift,CodaFi/swift,nathawes/swift,tkremenek/swift,apple/swift,therealbnut/swift,jtbandes/swift,bitjammer/swift,milseman/swift,tkremenek/swift,jtbandes/swift,tardieu/swift,airspeedswift/swift,devincoughlin/swift,harlanhaskins/swift,devincoughlin/swift,brentdax/swift,nathawes/swift,uasys/swift,huonw/swift,devincoughlin/swift,felix91gr/swift,Jnosh/swift,OscarSwanros/swift,aschwaighofer/swift,frootloops/swift,tjw/swift,manavgabhawala/swift,austinzheng/swift,jtbandes/swift,jopamer/swift,roambotics/swift,nathawes/swift,ben-ng/swift,gribozavr/swift,ahoppen/swift,aschwaighofer/swift,atrick/swift,bitjammer/swift,atrick/swift,xwu/swift,benlangmuir/swift,zisko/swift,devincoughlin/swift,gribozavr/swift,benlangmuir/swift,gottesmm/swift,rudkx/swift,ben-ng/swift,CodaFi/swift,hooman/swift,tinysun212/swift-windows,shajrawi/swift,apple/swift,danielmartin/swift,tardieu/swift,CodaFi/swift,JaSpa/swift,manavgabhawala/swift,gottesmm/swift,parkera/swift,djwbrown/swift,jtbandes/swift,parkera/swift,practicalswift/swift,glessard/swift,gregomni/swift,karwa/swift,tinysun212/swift-windows,CodaFi/swift,practicalswift/swift,djwbrown/swift,brentdax/swift,shajrawi/swift,zisko/swift,allevato/swift,shajrawi/swift,gottesmm/swift,JaSpa/swift,roambotics/swift,shahmishal/swift,jckarter/swift,hooman/swift,stephentyrone/swift,swiftix/swift,arvedviehweger/swift,lorentey/swift,danielmartin/swift,tinysun212/swift-windows,frootloops/swift,devincoughlin/swift,allevato/swift,arvedviehweger/swift,gottesmm/swift,felix91gr/swift,benlangmuir/swift,jckarter/swift,sschiau/swift,airspeedswift/swift,jmgc/swift,natecook1000/swift,tardieu/swift,rudkx/swift,karwa/swift,djwbrown/swift,jopamer/swift,karwa/swift,alblue/swift,Jnosh/swift,allevato/swift,zisko/swift,hooman/swift,lorentey/swift,gribozavr/swift,alblue/swift,milseman/swift,devincoughlin/swift,airspeedswift/swift,zisko/swift,swiftix/swift,gmilos/swift,tjw/swift,lorentey/swift,danielmartin/swift,allevato/swift,JaSpa/swift,deyton/swift,apple/swift,JGiola/swift,roambotics/swift,xedin/swift,jmgc/swift,gmilos/swift,tjw/swift,felix91gr/swift,bitjammer/swift,practicalswift/swift,OscarSwanros/swift,arvedviehweger/swift,djwbrown/swift,gribozavr/swift,danielmartin/swift,manavgabhawala/swift,OscarSwanros/swift,JaSpa/swift,sschiau/swift,gribozavr/swift,shahmishal/swift,ben-ng/swift,amraboelela/swift,ben-ng/swift,natecook1000/swift,jmgc/swift,Jnosh/swift,roambotics/swift,airspeedswift/swift,JaSpa/swift,xwu/swift,OscarSwanros/swift,zisko/swift,huonw/swift,ahoppen/swift,alblue/swift,apple/swift,OscarSwanros/swift,stephentyrone/swift,deyton/swift,jopamer/swift,gmilos/swift,JaSpa/swift,allevato/swift,felix91gr/swift,manavgabhawala/swift,swiftix/swift,xwu/swift,amraboelela/swift,xedin/swift,djwbrown/swift,calebd/swift,brentdax/swift,arvedviehweger/swift,uasys/swift,jopamer/swift,bitjammer/swift,frootloops/swift,brentdax/swift,airspeedswift/swift,therealbnut/swift,therealbnut/swift,nathawes/swift,tjw/swift,apple/swift,jckarter/swift,benlangmuir/swift,therealbnut/swift,benlangmuir/swift,return/swift,return/swift,gregomni/swift,jtbandes/swift,huonw/swift,felix91gr/swift,JGiola/swift,jopamer/swift,stephentyrone/swift,jopamer/swift,rudkx/swift,tinysun212/swift-windows,ben-ng/swift,lorentey/swift,natecook1000/swift,aschwaighofer/swift,ben-ng/swift,xwu/swift,jckarter/swift,amraboelela/swift,karwa/swift,codestergit/swift,jckarter/swift,hughbe/swift,parkera/swift,rudkx/swift,hughbe/swift,xwu/swift,glessard/swift,harlanhaskins/swift,alblue/swift,shajrawi/swift,Jnosh/swift,OscarSwanros/swift,jckarter/swift,xwu/swift,gottesmm/swift,atrick/swift,codestergit/swift,huonw/swift,harlanhaskins/swift,frootloops/swift,jtbandes/swift,lorentey/swift,allevato/swift,Jnosh/swift,codestergit/swift,tkremenek/swift,devincoughlin/swift,rudkx/swift,uasys/swift,practicalswift/swift,glessard/swift,swiftix/swift,austinzheng/swift,tkremenek/swift,JGiola/swift,Jnosh/swift,swiftix/swift,hooman/swift,tinysun212/swift-windows,CodaFi/swift,frootloops/swift,parkera/swift,amraboelela/swift,djwbrown/swift,gottesmm/swift,lorentey/swift,sschiau/swift,atrick/swift,uasys/swift,tardieu/swift,Jnosh/swift,gmilos/swift,lorentey/swift,manavgabhawala/swift,harlanhaskins/swift,sschiau/swift,jtbandes/swift,aschwaighofer/swift,jmgc/swift,sschiau/swift,tardieu/swift,shahmishal/swift,karwa/swift,calebd/swift,milseman/swift,huonw/swift,jopamer/swift,milseman/swift,felix91gr/swift,arvedviehweger/swift,jmgc/swift,glessard/swift,sschiau/swift,codestergit/swift,stephentyrone/swift,danielmartin/swift,stephentyrone/swift,ahoppen/swift,codestergit/swift,gmilos/swift,atrick/swift,practicalswift/swift,calebd/swift,milseman/swift,JGiola/swift,parkera/swift,ahoppen/swift,shajrawi/swift,danielmartin/swift,amraboelela/swift,tkremenek/swift,roambotics/swift,deyton/swift,lorentey/swift,alblue/swift,airspeedswift/swift,gmilos/swift,hughbe/swift,alblue/swift,shahmishal/swift,practicalswift/swift,deyton/swift,return/swift,milseman/swift,amraboelela/swift,tjw/swift,bitjammer/swift,practicalswift/swift,swiftix/swift,tardieu/swift,brentdax/swift,uasys/swift,jmgc/swift,manavgabhawala/swift,gregomni/swift,xedin/swift,JaSpa/swift,arvedviehweger/swift,karwa/swift,stephentyrone/swift,felix91gr/swift,gregomni/swift,austinzheng/swift,return/swift,natecook1000/swift,arvedviehweger/swift,tinysun212/swift-windows,hooman/swift,sschiau/swift,natecook1000/swift,nathawes/swift,austinzheng/swift,allevato/swift,uasys/swift,rudkx/swift,deyton/swift,tjw/swift,hooman/swift,jmgc/swift,xedin/swift,zisko/swift,gregomni/swift,xwu/swift,gribozavr/swift,ben-ng/swift,shahmishal/swift,gribozavr/swift,apple/swift,gregomni/swift,calebd/swift,karwa/swift,milseman/swift,danielmartin/swift,calebd/swift,xedin/swift,parkera/swift,gottesmm/swift,austinzheng/swift,harlanhaskins/swift,natecook1000/swift,austinzheng/swift,tjw/swift,therealbnut/swift,codestergit/swift,return/swift,deyton/swift,huonw/swift,codestergit/swift,brentdax/swift,glessard/swift,shajrawi/swift,practicalswift/swift,shahmishal/swift,sschiau/swift,hughbe/swift,benlangmuir/swift,zisko/swift,shajrawi/swift,return/swift,tinysun212/swift-windows