Reorganize test utilities, add unit tests.

[drroe]

Reorganization of test utilities to hopefully make things simpler to maintain. Instead of being in a directory separate from test, they are now in a subdirectory of test.

• Move ndiff.awk to a utilities subdirectory of the test directory; it is only used by tests and really belongs there.
• Delete the nproc program with a (hopefully) simpler to use and maintain shell script that determines number of processes by counting how many echos the current $DO_PARALLEL will invoke. Also have this in test/utilities.
• Add unit tests that were in an external repository here. The idea is that they test very basic units of functionality and are either pass/fail. Try to make sure I don't break fundamental functionality in e.g. the ArgList class. These will be tested on Jenkins.

[drroe]

Grr - I hate when CI fails due to the infrastructure, although I guess you get what you pay for...

E: Failed to fetch http://azure.archive.ubuntu.com/ubuntu/pool/main/n/nvidia-settings/libxnvctrl0_440.82-0ubuntu0.20.04.1_amd64.deb  404  Not Found [IP: 52.147.219.192 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

[drroe]

Looks like adding apt update to Actions did the trick. LGTM failed due to timeout but that seems to be a problem on their end.

[drroe]

I don't know why LGTM is failing. It just keeps timing out. The last step is this:

[148/150 eval 56ms] Evaluation done; writing results to codeql-cpp/Metrics/Files/FLinesOfComments.bqrs.
Starting evaluation of codeql-cpp/Metrics/Files/FNumberOfTests.ql.

There are no error messages as far as I can tell. I'm tired of debugging it. If Jenkins passes again I'm just going to merge.