Add unit tests for the assignWith value witnesses of opaque existential boxes
Add unit tests for the assignWith value witnesses of opaque existential boxes

More tests for the failure from rdar://31955457

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