[ConstraintSystem] Adjust `getCalleeLocator` and `simplifyLocator` to handle `ArgumentAttribute`
[ConstraintSystem] Adjust `getCalleeLocator` and `simplifyLocator` to handle `ArgumentAttribute`

- `getCalleeLocator`, if given locator ends at `ArgumentAttribute`
  strip the last element which makes sure that produced locator
  always refers directly to argument-to-parameter conversion.

- `simplifyLocator`, always leave `ArgumentAttribute` in the path
  because it's useful for diagnostics.

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