[Constraint system] Add conversion constraint for typed patterns.
[Constraint system] Add conversion constraint for typed patterns.

For typed patterns, the sub pattern type must be convertible to the type
provided to the pattern.

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