[Gardening] Migrate complete_expr_postfix_begin test to use new batching
[Gardening] Migrate complete_expr_postfix_begin test to use new batching

hooman/swift,roambotics/swift,benlangmuir/swift,parkera/swift,glessard/swift,JGiola/swift,jmgc/swift,gregomni/swift,parkera/swift,hooman/swift,ahoppen/swift,rudkx/swift,parkera/swift,xwu/swift,benlangmuir/swift,xwu/swift,JGiola/swift,apple/swift,parkera/swift,jmgc/swift,parkera/swift,ahoppen/swift,benlangmuir/swift,tkremenek/swift,parkera/swift,atrick/swift,rudkx/swift,roambotics/swift,rudkx/swift,atrick/swift,gregomni/swift,ahoppen/swift,JGiola/swift,rudkx/swift,benlangmuir/swift,ahoppen/swift,hooman/swift,apple/swift,hooman/swift,tkremenek/swift,hooman/swift,atrick/swift,glessard/swift,jmgc/swift,apple/swift,xwu/swift,glessard/swift,tkremenek/swift,ahoppen/swift,roambotics/swift,parkera/swift,benlangmuir/swift,JGiola/swift,rudkx/swift,atrick/swift,apple/swift,atrick/swift,xwu/swift,roambotics/swift,apple/swift,roambotics/swift,parkera/swift,gregomni/swift,tkremenek/swift,jmgc/swift,gregomni/swift,xwu/swift,ahoppen/swift,roambotics/swift,tkremenek/swift,tkremenek/swift,hooman/swift,tkremenek/swift,gregomni/swift,jmgc/swift,benlangmuir/swift,hooman/swift,glessard/swift,xwu/swift,glessard/swift,jmgc/swift,atrick/swift,rudkx/swift,gregomni/swift,xwu/swift,JGiola/swift,jmgc/swift,glessard/swift,JGiola/swift,apple/swift