test_runner: fix `skip` and `todo`

fix node:test skip method to better match existing well known APIs

before this change, skipping worked only this way:

test('a', {skip: true}, () => {});
test('a', (t) => {
	t.skip();
});

after this fix, both these ways still skip the test the same way, but you can also skip using test.skip('name', fn) which did not work before.

also - the docs was taken from tap docs since this follows the same behavior