tests: remove final reference to formula_exist
tests: remove final reference to formula_exist

Homebrew/brew,EricFromCanada/brew,claui/brew,claui/brew,Homebrew/brew,konqui/brew,Homebrew/brew,konqui/brew,nandub/brew,MikeMcQuaid/brew,JCount/brew,vitorgalvao/brew,JCount/brew,vitorgalvao/brew,konqui/brew,vitorgalvao/brew,claui/brew,Homebrew/brew,sjackman/homebrew,nandub/brew,sjackman/homebrew,konqui/brew,nandub/brew,MikeMcQuaid/brew,JCount/brew,vitorgalvao/brew,JCount/brew,sjackman/homebrew,EricFromCanada/brew,sjackman/homebrew,claui/brew,MikeMcQuaid/brew,EricFromCanada/brew,nandub/brew,MikeMcQuaid/brew,EricFromCanada/brew