[ClangImporter] Handle lookup tables with many entries (#17265)
[ClangImporter] Handle lookup tables with many entries (#17265)

In particular, there are frameworks with more than 65536 entries for
'init' as a base name.

I can't think of a test case for this besides actually adding such a
massive framework, but the assertions that were added here should
catch the issue in Debug builds if it ever comes up again. I'm going
to go harden everything else that uses this API next.

rdar://problem/40828315
aschwaighofer/swift,apple/swift,tkremenek/swift,jopamer/swift,jopamer/swift,natecook1000/swift,stephentyrone/swift,alblue/swift,karwa/swift,parkera/swift,lorentey/swift,xwu/swift,sschiau/swift,alblue/swift,sschiau/swift,amraboelela/swift,CodaFi/swift,roambotics/swift,danielmartin/swift,stephentyrone/swift,practicalswift/swift,airspeedswift/swift,jopamer/swift,parkera/swift,jopamer/swift,apple/swift,xwu/swift,alblue/swift,devincoughlin/swift,shajrawi/swift,glessard/swift,CodaFi/swift,sschiau/swift,sschiau/swift,allevato/swift,gribozavr/swift,amraboelela/swift,practicalswift/swift,sschiau/swift,gribozavr/swift,glessard/swift,danielmartin/swift,parkera/swift,xwu/swift,lorentey/swift,karwa/swift,hooman/swift,jckarter/swift,stephentyrone/swift,nathawes/swift,jckarter/swift,parkera/swift,allevato/swift,nathawes/swift,hooman/swift,atrick/swift,airspeedswift/swift,roambotics/swift,jckarter/swift,brentdax/swift,nathawes/swift,gribozavr/swift,tkremenek/swift,danielmartin/swift,roambotics/swift,rudkx/swift,atrick/swift,JGiola/swift,xedin/swift,harlanhaskins/swift,gribozavr/swift,JGiola/swift,brentdax/swift,danielmartin/swift,jopamer/swift,rudkx/swift,shahmishal/swift,gregomni/swift,tkremenek/swift,aschwaighofer/swift,jopamer/swift,gregomni/swift,austinzheng/swift,lorentey/swift,danielmartin/swift,shajrawi/swift,karwa/swift,roambotics/swift,brentdax/swift,roambotics/swift,practicalswift/swift,xwu/swift,harlanhaskins/swift,devincoughlin/swift,natecook1000/swift,shahmishal/swift,JGiola/swift,allevato/swift,jmgc/swift,aschwaighofer/swift,brentdax/swift,glessard/swift,gribozavr/swift,austinzheng/swift,amraboelela/swift,xedin/swift,shajrawi/swift,apple/swift,brentdax/swift,amraboelela/swift,airspeedswift/swift,gribozavr/swift,karwa/swift,lorentey/swift,CodaFi/swift,practicalswift/swift,practicalswift/swift,jckarter/swift,stephentyrone/swift,shahmishal/swift,brentdax/swift,jmgc/swift,gregomni/swift,xedin/swift,nathawes/swift,harlanhaskins/swift,gribozavr/swift,airspeedswift/swift,natecook1000/swift,glessard/swift,jckarter/swift,xwu/swift,allevato/swift,lorentey/swift,aschwaighofer/swift,xedin/swift,ahoppen/swift,rudkx/swift,rudkx/swift,sschiau/swift,allevato/swift,parkera/swift,karwa/swift,shajrawi/swift,rudkx/swift,tkremenek/swift,jmgc/swift,JGiola/swift,roambotics/swift,harlanhaskins/swift,alblue/swift,apple/swift,tkremenek/swift,austinzheng/swift,practicalswift/swift,brentdax/swift,shajrawi/swift,aschwaighofer/swift,benlangmuir/swift,benlangmuir/swift,hooman/swift,danielmartin/swift,natecook1000/swift,xwu/swift,CodaFi/swift,alblue/swift,shahmishal/swift,karwa/swift,devincoughlin/swift,nathawes/swift,practicalswift/swift,JGiola/swift,hooman/swift,stephentyrone/swift,lorentey/swift,xedin/swift,JGiola/swift,aschwaighofer/swift,austinzheng/swift,devincoughlin/swift,natecook1000/swift,benlangmuir/swift,alblue/swift,jckarter/swift,allevato/swift,shahmishal/swift,ahoppen/swift,tkremenek/swift,CodaFi/swift,airspeedswift/swift,devincoughlin/swift,sschiau/swift,austinzheng/swift,xedin/swift,harlanhaskins/swift,hooman/swift,natecook1000/swift,ahoppen/swift,gregomni/swift,jmgc/swift,apple/swift,xedin/swift,hooman/swift,shajrawi/swift,alblue/swift,jckarter/swift,stephentyrone/swift,harlanhaskins/swift,lorentey/swift,xedin/swift,hooman/swift,danielmartin/swift,benlangmuir/swift,airspeedswift/swift,shajrawi/swift,atrick/swift,parkera/swift,ahoppen/swift,austinzheng/swift,atrick/swift,ahoppen/swift,karwa/swift,jopamer/swift,jmgc/swift,airspeedswift/swift,devincoughlin/swift,stephentyrone/swift,CodaFi/swift,amraboelela/swift,CodaFi/swift,tkremenek/swift,atrick/swift,shahmishal/swift,shahmishal/swift,sschiau/swift,benlangmuir/swift,atrick/swift,ahoppen/swift,allevato/swift,parkera/swift,devincoughlin/swift,jmgc/swift,benlangmuir/swift,practicalswift/swift,rudkx/swift,glessard/swift,shahmishal/swift,harlanhaskins/swift,nathawes/swift,nathawes/swift,apple/swift,jmgc/swift,amraboelela/swift,austinzheng/swift,glessard/swift,parkera/swift,shajrawi/swift,xwu/swift,gregomni/swift,karwa/swift,devincoughlin/swift,lorentey/swift,gregomni/swift,natecook1000/swift,amraboelela/swift,gribozavr/swift,aschwaighofer/swift