…ffects

`expect.fail()` was mistakenly introduced in graphql#3760 under the assumption that expect.fail() will always cause the test to fail, and that `.next()` should be called at most once.

Actually, thought, `expect.fail()` just throws an error, `.next()` is called more than once, the error is produced and wrapped by GraphQL, but then it is filtered, so the test ultimately passes.

Fortunately, that's actually the desired behavior! It's ok if the number of calls to `.next()` is more than 1 (in our case it is 2). The exact number of calls to `.next()` depends on the # of ticks that it takes for the erroring deferred fragment to resolve, which should be as low as possible, but that is a separate objective (with other PRs in the mix already aimed at reducing).

So the test as written is intending to be overly strict, but is not actually meeting that goal and so functions as desires. This PR makes no change to the test semantics, but changes the comment, the coverage ignore statement, and removes the potentially confusing use of `expect.fail`, so that the test semantics are more clearly apparent.

…ffects

…into fragment-args