Update CDC tests to print out the stderr when tests fail

[NKTomHaygarth]

When running the tests for the Core Dump Composer the error output was not being printed. This was making things a little difficult to track down where the tests might be failing if the Composer was hitting an error path.

This PR just adds println!("{}", String::from_utf8_lossy(&cdc.stderr)); underneath all locations where cdc.stdout is already getting printed in the tests for the Composer

[No9]

Thank you very much for this PR and happy to land it if we can resolve the clippy issue.

Please can you either rebase this to this PR #116
or wait until 116 landed and rebase to main.

Thank again for the contribution.

[NKTomHaygarth]

You're welcome. I'm away until Monday if the PR #116 isn't merged in by then I can rebase to that when I'm back

[No9]

Simple change so LGTM - @NKTomHaygarth Can you rebase and we will pull this in for the next release

[No9]

Hey @NKTomHaygarth Just doing some house keeping.
do you still want this in or can I close this?

[NKTomHaygarth]

Hey @No9, sorry things got a little busy towards the end of last year so I had to shelve some of the stuff I was doing. I will look into rebasing this PR later this week and hopefully get it ready to merge in.

[No9]

No worries - thanks for coming back to it.

[No9]

Thanks for following up on this @NKTomHaygarth