Allow bailing early when test fails

Needs a *Bail Out*/*Fail Fast* strategy ### What is the problem this feature will solve? Not having to sift through a jumbled up mess of stack traces as I'm cleaning up tests after significant refactoring of the unit i'm testing. Spit out the failing test and it's stack trace, then Exit 1 as *soon* as a test fails ### Proposal A bail flag, i.e `--bail` that hints to the runner that a failure should report and exit. ### Alternatives Cooking up an [Abort Signal](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal) wiring but that's really me writing machinery code to test.. the code... which is just bad taste, at least in most cases.