[Serialization] Make sure to emit an XREF before XREF_OPAQUE_RETURN_TYPE_PATH_PIECE
[Serialization] Make sure to emit an XREF before XREF_OPAQUE_RETURN_TYPE_PATH_PIECE

We might have an opaque return type path piece after a generic type
param type, so make sure to emit the XREF entry before the opaque return
type path piece as well.

Fixes rdar://53958358

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