workflows/tests: tweak step naming.
workflows/tests: tweak step naming.

This should make it a bit more obvious what is being tested each time.

The homebrew-core/linuxbrew-core style step actually runs the same
command but, as far as I can tell, there's no way of altering the string
that's output as the `name` based on the OS.

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