Fix FileTest>>testCommonPrefixOfAnd which fails on AppVeyor CI build
Fix FileTest>>testCommonPrefixOfAnd which fails on AppVeyor CI build

blairmcg/Dolphin,dolphinsmalltalk/Dolphin,blairmcg/Dolphin,objectarts/Dolphin,dolphinsmalltalk/Dolphin,jgfoster/Dolphin,objectarts/Dolphin,dolphinsmalltalk/Dolphin,shoshanatech/Dolphin,shoshanatech/Dolphin,jgfoster/Dolphin,dolphinsmalltalk/Dolphin,jgfoster/Dolphin,jgfoster/Dolphin,blairmcg/Dolphin,blairmcg/Dolphin,shoshanatech/Dolphin,shoshanatech/Dolphin