test: kill all subprocesses on timeout.
test: kill all subprocesses on timeout.

Fixes #5885.

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