Demangling: use `assert` over `llvm_unreachable`
Demangling: use `assert` over `llvm_unreachable`

Avoid a dependency on LLVMSupport at runtime through the `llvm_unreachable`.
This would pull in `llvm_unreachable_internal` in debug builds, which requires a
runtime dependency on LLVMSupport which increases the size of the binary
considerably.

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