formula_assertions: add assert_not_match compat
formula_assertions: add assert_not_match compat

There are some formulae using this method:
https://github.com/Homebrew/homebrew-core/search?q=assert_not_match&type=
JCount/brew,nandub/brew,Homebrew/brew,sjackman/homebrew,MikeMcQuaid/brew,EricFromCanada/brew,MikeMcQuaid/brew,claui/brew,claui/brew,nandub/brew,JCount/brew,Homebrew/brew,EricFromCanada/brew,Homebrew/brew,MikeMcQuaid/brew,EricFromCanada/brew,vitorgalvao/brew,Homebrew/brew,vitorgalvao/brew,JCount/brew,sjackman/homebrew,nandub/brew,JCount/brew,vitorgalvao/brew,MikeMcQuaid/brew,sjackman/homebrew,claui/brew,sjackman/homebrew,claui/brew,EricFromCanada/brew,nandub/brew,vitorgalvao/brew