[sil] Add a new API ValueBase::getSingleUser()
[sil] Add a new API ValueBase::getSingleUser()

This API returns nullptr if the ValueBase has more than one user and an
Operand * otherwise.

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