Add on to the mitigation in https://github.com/visionmedia/supertest/pull/728/commits.

• As [].every(val => typeof val === 'number')) evaluates to true in legit cases where we expect the body to return empty array the tests will fail.
• Change is to also check for array length and defaulting to consider it as body instead of empty list of statues.