Bugfix - Data race + Warning

[aiFigueiredo]

This PR aims to address #825

What was done:

1. Added unit tests while on master to cover any possible outcomes of ParseManager.parseMultiple including a measure test.
2. Addressed the warning by removing DispatchQueue.concurrentPerform
3. Committed the baseline plists (set while on master writing the tests). Let me know if that shouldn't be committed.

Notes:

1. Checked test run times and it seems this approach takes less time to complete:

(used the existing test as a baseline)

2. This approach drops DispatchQueue.concurrentPerform but maybe that is not something that should be done?
3. An alternate approach to fixing the data race could be a lock. Let me know if that is preferred.