Add options to treat todo/skip as failures

[isaacs]

In most normal cases, the right thing to do is treat todo and skip tests as if they were passing, regardless of status.

And, an empty test (or just a file that doesn't produce any TAP test points) is treated as a skipped test.

This is almost always the right thing to do, but it prevents a workflow that I'm sort of finding to be nice.

1. Create a new package, with a bunch of files at src/*.ts
2. Create a coverage map file map.js which does export default t => t.replace(/^test/, 'src')
3. Create an empty test for each source unit: for i in src/*; do touch ${i/src/test}; done
4. Treat the skipped tests as my worklist.

It would be nice if I could do this, but avoid running all the tests I wrote as I'm working through the list.

$ tap --save todo.txt --fail-skip --fail-todo

Then the todo and skip tests would log as failures, and get saved to the file, and I could keep whittling it down until everything is done.

Could also be useful as a sort of lint rule in CI, to avoid merging PRs that still have action items.

[isaacs]

My workaround has been to either put an artificial (await import('tap')).fail('todo') in each of the empty tests, or use find test -size 0 as my worklist, but both feel like hacks.