Aggregate with $out should ignore batchSize option

When executing an aggregation pipeline with an $out stage, passing a batchSize of zero results in the pipeline never executing. A test case was originally added to the CRUD spec test suite in SPEC-826 to ensure that the batchSize is ignored, but we didn't catch the bug in PHPLIB due to some faulty logic in our test runner.

This ticket should correct the behavior in the Aggregate operation class and also fix the test runner.