4a03145c1c
Ensure that a non-zero exit code is set both for missing random dylibs and random missing dependencies. Additionally, while we are here, drastically trim down the public interface for this class to the bare minimum and allow getting the output from `display_test_output` as a variable. Fixes issue mentioned by @ilovezfs in: https://github.com/Homebrew/brew/pull/3940#issuecomment-383794520