build: canonicalise source path before use (NFC)
build: canonicalise source path before use (NFC)

If the source tree is checked out into a patch behind a symlink, the path can
get expanded and fail tests.  Be more resilient by canonicalise the path prior
to use.

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