build: remove set of internal CMake variable
build: remove set of internal CMake variable

CMAKE_EXECUTABLE_FORMAT is set by CMake based on the target.  We were setting it
in certain cases.  Uniformly rely on CMake configuring the parameter correctly.
This should have no impact on the build.

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