Add Test To Verify Rewritten *.pyc Files Are Readable

[holmanb]

Additional test verifies that rewrite->compile->write->read results in a valid pyc file.

closes #9521

[nicoddemus]

Thanks!

Out of curiosity, why do you say it was not covered before?

[holmanb]

Out of curiosity, why do you say it was not covered before?

I suppose that was misleading wording, apologies. I see that tests exist for _read_pyc(), _write_pyc(), and _rewrite_test() (which is called in exec_module()). What I don't see are any tests that verify that a pyc written with _write_pyc() is actually valid and readable with _read_pyc(). This "covers" that case. If this is already tested in some other way that I haven't considered I can drop this PR.

[nicoddemus]

No that's fine, thanks for the clarification! I think such a test is valuable to have. 👍

[nicoddemus]

Backport: #9530