Base Test Classes are inefficient

[jasongilanfarr]

parseq-test has a base test class that creates an engine and threadpool per test class instead of one shared one overall. The former is excellent for testing parseq itself in isolation, but the latter is better for testing usages of parseq in that it doesn't create hundreds of thousands of threads.

Happy to contribute a patch too.

[BrianPin]

@jasongilanfarr Hi Jason, that sounds making sense, I am happy to see the patch and contribution. I will be a little bit worried the existing test cases which was originally in a mutually exclusive condition and now being in a shared resource, what will happen? flaky test? We will see, but happy to see the contribution