Analyze and repair jstests/sharding/test_resharding_test_fixture_shutdown_retry_needed.js for coding that may cause the test to generate false-positive failures (i.e. flakiness)

When finished, please answer the following questions:

1. What test behaviors does this file have that could cause false-positive failures? (e.g. dependence on timing, dependence on specific order of events)

2. How were the above behaviors removed or mitigated? Describe the fix. If no mitigation was made, explain.

If you have implemented a fix that may be generally applicable to test writers, share your knowledge by revising this document, Notes to Writers of Sharding Jstests.